Extended version of Rambda(utility library) - Documentation
Rambda is smaller and faster alternative to the popular functional programming library Ramda. - Documentation
Rambdax passthrough all Rambda methods and introduce some new functions.
The idea of Rambdax is to extend Rambda without worring for Ramda compatibility.
import { composeAsync, filter, delay, mapAsync } from 'rambdax'
const result = await composeAsync(
mapAsync(async x => {
await delay(100)
return x + 1
}),
filter(x => x > 1)
)([1, 2, 3])
// => [3, 4]
You can test this example in Rambda's REPL
R.path, R.paths, R.assocPath and R.lensPathStandard usage of R.path is R.path(['a', 'b'], {a: {b: 1} }).
In Rambda you have the choice to use dot notation(which is arguably more readable):
R.path('a.b', {a: {b: 1} })
R.pick and R.omitSimilar to dot notation, but the separator is comma(,) instead of dot(.).
R.pick('a,b', {a: 1 , b: 2, c: 3} })
// No space allowed between properties
Rambdax implements some methods from Ramda community projects, such as R.lensSatisfies, R.lensEq and R.viewOr.
Alternative TS definitions are available as rambdax/immutable. These are Rambdax definitions linted with ESLint functional/prefer-readonly-type plugin.
yarn add rambdax
For UMD usage either use ./dist/rambdax.umd.js or the following CDN link:
https://unpkg.com/rambdax@CURRENT_VERSION/dist/rambdax.umd.js
import {compose, add} from 'https://raw.githubusercontent.com/selfrefactor/rambdax/master/dist/rambdax.esm.js'
Rambda's type detects async functions and unresolved Promises. The returned values are 'Async' and 'Promise'.
Rambda's type handles NaN input, in which case it returns NaN.
Rambda's forEach can iterate over objects not only arrays.
Rambda's map, filter, partition when they iterate over objects, they pass property and input object as predicate's argument.
Rambda's filter returns empty array with bad input(null or undefined), while Ramda throws.
Ramda's clamp work with strings, while Rambda's method work only with numbers.
Error handling, when wrong inputs are provided, may not be the same. This difference will be better documented once all brute force tests are completed.
Typescript definitions between rambda and @types/ramda may vary.
There are methods which are benchmarked only with Ramda and Rambda(i.e. no Lodash).
Note that some of these methods, are called with and without curring. This is done in order to give more detailed performance feedback.
The benchmarks results are produced from latest versions of Rambda, Lodash(4.17.20) and Ramda(0.27.1).
| method | Rambda | Ramda | Lodash |
|---|---|---|---|
| add | 96.25% slower | 96.24% slower | 🚀 Fastest |
| adjust | 🚀 Fastest | 5.52% slower | 🔳 |
| all | 🚀 Fastest | 94.95% slower | 🔳 |
| allPass | 🚀 Fastest | 98.95% slower | 🔳 |
| any | 🚀 Fastest | 98.18% slower | 6.18% slower |
| anyPass | 🚀 Fastest | 99.09% slower | 🔳 |
| append | 🚀 Fastest | 84.09% slower | 🔳 |
| applySpec | 🚀 Fastest | 75.73% slower | 🔳 |
| assoc | 87.98% slower | 57.39% slower | 🚀 Fastest |
| clone | 🚀 Fastest | 96.03% slower | 91.75% slower |
| compose | 🚀 Fastest | 96.45% slower | 77.83% slower |
| converge | 49.12% slower | 🚀 Fastest | 🔳 |
| curry | 🚀 Fastest | 34.9% slower | 🔳 |
| curryN | 63.32% slower | 🚀 Fastest | 🔳 |
| defaultTo | 🚀 Fastest | 50.3% slower | 🔳 |
| drop | 🚀 Fastest | 97.45% slower | 🔳 |
| dropLast | 🚀 Fastest | 97.07% slower | 🔳 |
| equals | 72.11% slower | 79.48% slower | 🚀 Fastest |
| filter | 🚀 Fastest | 94.74% slower | 58.18% slower |
| find | 🚀 Fastest | 98.2% slower | 88.96% slower |
| findIndex | 🚀 Fastest | 97.97% slower | 79.39% slower |
| flatten | 6.56% slower | 95.38% slower | 🚀 Fastest |
| ifElse | 🚀 Fastest | 70.97% slower | 🔳 |
| includes | 🚀 Fastest | 71.7% slower | 🔳 |
| indexOf | 🚀 Fastest | 84.08% slower | 7.86% slower |
| init | 94.42% slower | 97.55% slower | 🚀 Fastest |
| is | 🚀 Fastest | 11.72% slower | 🔳 |
| isEmpty | 51.68% slower | 93.82% slower | 🚀 Fastest |
| last | 🚀 Fastest | 99.64% slower | 1.05% slower |
| lastIndexOf | 🚀 Fastest | 42.38% slower | 🔳 |
| map | 🚀 Fastest | 69.63% slower | 4.68% slower |
| match | 🚀 Fastest | 46.75% slower | 🔳 |
| merge | 63.55% slower | 🚀 Fastest | 55.25% slower |
| none | 🚀 Fastest | 98.22% slower | 🔳 |
| omit | 🚀 Fastest | 70.66% slower | 97.56% slower |
| over | 🚀 Fastest | 50.77% slower | 🔳 |
| path | 🚀 Fastest | 74.94% slower | 5.72% slower |
| pick | 🚀 Fastest | 26.29% slower | 86.82% slower |
| prop | 🚀 Fastest | 89.89% slower | 🔳 |
| propEq | 🚀 Fastest | 95.26% slower | 🔳 |
| range | 95.17% slower | 90.22% slower | 🚀 Fastest |
| reduce | 52.76% slower | 74.02% slower | 🚀 Fastest |
| repeat | 85.91% slower | 95.31% slower | 🚀 Fastest |
| replace | 0.47% slower | 28.13% slower | 🚀 Fastest |
| set | 🚀 Fastest | 36.26% slower | 🔳 |
| sort | 🚀 Fastest | 63.15% slower | 🔳 |
| sortBy | 🚀 Fastest | 61.57% slower | 88.88% slower |
| split | 🚀 Fastest | 85.34% slower | 33.69% slower |
| splitEvery | 🚀 Fastest | 90.18% slower | 🔳 |
| take | 93.44% slower | 98.04% slower | 🚀 Fastest |
| takeLast | 92.61% slower | 98.83% slower | 🚀 Fastest |
| test | 🚀 Fastest | 94.42% slower | 🔳 |
| type | 18.91% slower | 🚀 Fastest | 🔳 |
| uniq | 98.98% slower | 96.58% slower | 🚀 Fastest |
| update | 🚀 Fastest | 38.88% slower | 🔳 |
| view | 🚀 Fastest | 82.21% slower | 🔳 |
Walmart Canada reported by w-b-dev
add(a: number, b: number): number
It adds a and b.
:boom: It doesn't work with strings, as the inputs are parsed to numbers before calculation.
R.add(2, 3) // => 5
Try this R.add example in Rambda REPL
export function add(a, b){
if (arguments.length === 1) return _b => add(a, _b)
return Number(a) + Number(b)
}
import { add } from './add'
test('with number', () => {
expect(add(2, 3)).toEqual(5)
expect(add(7)(10)).toEqual(17)
})
test('string is bad input', () => {
expect(add('foo', 'bar')).toBeNaN()
})
test('ramda specs', () => {
expect(add('1', '2')).toEqual(3)
expect(add(1, '2')).toEqual(3)
expect(add(true, false)).toEqual(1)
expect(add(null, null)).toEqual(0)
expect(add(undefined, undefined)).toEqual(NaN)
expect(add(new Date(1), new Date(2))).toEqual(3)
})
adjust<T>(index: number, replaceFn: (x: T) => T, list: T[]): T[]
It replaces index in array list with the result of replaceFn(list[i]).
R.adjust(
0,
a => a + 1,
[0, 100]
) // => [1, 100]
Try this R.adjust example in Rambda REPL
import { curry } from './curry'
function adjustFn(
index, replaceFn, list
){
const actualIndex = index < 0 ? list.length + index : index
if (index >= list.length || actualIndex < 0) return list
const clone = list.slice()
clone[ actualIndex ] = replaceFn(clone[ actualIndex ])
return clone
}
export const adjust = curry(adjustFn)
import { add } from './add'
import { adjust } from './adjust'
import { pipe } from './pipe'
const list = [ 0, 1, 2 ]
const expected = [ 0, 11, 2 ]
test('happy', () => {})
test('happy', () => {
expect(adjust(
1, add(10), list
)).toEqual(expected)
})
test('with curring type 1 1 1', () => {
expect(adjust(1)(add(10))(list)).toEqual(expected)
})
test('with curring type 1 2', () => {
expect(adjust(1)(add(10), list)).toEqual(expected)
})
test('with curring type 2 1', () => {
expect(adjust(1, add(10))(list)).toEqual(expected)
})
test('with negative index', () => {
expect(adjust(
-2, add(10), list
)).toEqual(expected)
})
test('when index is out of bounds', () => {
const list = [ 0, 1, 2, 3 ]
expect(adjust(
4, add(1), list
)).toEqual(list)
expect(adjust(
-5, add(1), list
)).toEqual(list)
})
all<T>(predicate: (x: T) => boolean, list: T[]): boolean
It returns true, if all members of array list returns true, when applied as argument to predicate function.
const list = [ 0, 1, 2, 3, 4 ]
const predicate = x => x > -1
const result = R.all(predicate, list)
// => true
Try this R.all example in Rambda REPL
export function all(predicate, list){
if (arguments.length === 1) return _list => all(predicate, _list)
for (let i = 0; i < list.length; i++){
if (!predicate(list[ i ])) return false
}
return true
}
import { all } from './all'
const list = [ 0, 1, 2, 3, 4 ]
test('when true', () => {
const fn = x => x > -1
expect(all(fn)(list)).toBeTrue()
})
test('when false', () => {
const fn = x => x > 2
expect(all(fn, list)).toBeFalse()
})
allFalse(...inputs: any[]): boolean
It returns true if all inputs arguments are falsy(empty objects and empty arrays are considered falsy).
Functions are valid inputs, but these functions cannot have their own arguments.
This method is very similar to R.anyFalse, R.anyTrue and R.allTrue
R.allFalse(0, null, [], {}, '', () => false)
// => true
Try this R.allFalse example in Rambda REPL
import { isTruthy } from './_internals/isTruthy'
import { type } from './type'
export function allFalse(...inputs){
let counter = 0
while (counter < inputs.length){
const x = inputs[ counter ]
if (type(x) === 'Function'){
if (isTruthy(x())){
return false
}
} else if (isTruthy(x)){
return false
}
counter++
}
return true
}
import { runTests } from 'helpers-fn'
import { allFalse } from './allFalse'
const happy = { ok : [ () => false, () => [], () => {}, null, false, [] ] }
const withArray = { fail : [ ...happy.ok, [ 1 ] ] }
const withObject = { fail : [ ...happy.ok, { a : 1 } ] }
const withFunction = { fail : [ ...happy.ok, () => ({ a : 1 }) ] }
const withBoolean = { fail : [ ...happy.ok, true ] }
const testData = {
label : 'R.allFalse',
data : [ happy, withArray, withObject, withFunction, withBoolean ],
fn : input => allFalse(...input),
}
runTests(testData)
allPass<T>(predicates: ((x: T) => boolean)[]): (input: T) => boolean
It returns true, if all functions of predicates return true, when input is their argument.
const input = {
a : 1,
b : 2,
}
const predicates = [
x => x.a === 1,
x => x.b === 2,
]
const result = R.allPass(predicates)(input) // => true
Try this R.allPass example in Rambda REPL
export function allPass(predicates){
return input => {
let counter = 0
while (counter < predicates.length){
if (!predicates[ counter ](input)){
return false
}
counter++
}
return true
}
}
import { allPass } from './allPass'
test('happy', () => {
const rules = [ x => typeof x === 'number', x => x > 10, x => x * 7 < 100 ]
expect(allPass(rules)(11)).toBeTrue()
expect(allPass(rules)(undefined)).toBeFalse()
})
test('when returns true', () => {
const conditionArr = [ val => val.a === 1, val => val.b === 2 ]
expect(allPass(conditionArr)({
a : 1,
b : 2,
})).toBeTrue()
})
test('when returns false', () => {
const conditionArr = [ val => val.a === 1, val => val.b === 3 ]
expect(allPass(conditionArr)({
a : 1,
b : 2,
})).toBeFalse()
})
allTrue(...input: any[]): boolean
It returns true if all inputs arguments are truthy(empty objects and empty arrays are considered falsy).
R.allTrue(1, true, {a: 1}, [1], 'foo', () => true)
// => true
Try this R.allTrue example in Rambda REPL
import { isFalsy } from './_internals/isFalsy'
import { type } from './type'
export function allTrue(...inputs){
let counter = 0
while (counter < inputs.length){
const x = inputs[ counter ]
if (type(x) === 'Function'){
if (isFalsy(x())){
return false
}
} else if (isFalsy(x)){
return false
}
counter++
}
return true
}
import { allTrue } from './allTrue'
test('with functions', () => {
const foo = () => 1
const bar = () => false
const baz = () => JSON.parse('{sda')
const result = allTrue(
foo, bar, baz
)
expect(result).toBeFalse()
})
test('usage with non boolean', () => {
const foo = { a : 1 }
const baz = [ 1, 2, 3 ]
const result = allTrue(
foo, foo, baz
)
expect(result).toBeTrue()
})
test('usage with boolean', () => {
const foo = 4
const baz = [ 1, 2, 3 ]
const result = allTrue(foo > 2, baz.length === 3)
expect(result).toBeTrue()
})
test('escapes early - case 0', () => {
const foo = undefined
const result = allTrue(foo, () => foo.a)
expect(result).toBeFalse()
})
test('escapes early - case 1', () => {
const foo = null
const result = allTrue(foo, () => foo.a)
expect(result).toBeFalse()
})
test('escapes early - case 2', () => {
const foo = { a : 'bar' }
const result = allTrue(
foo, foo.a, foo.a.b
)
expect(result).toBeFalse()
})
test('escapes early - case 3', () => {
const foo = { a : { b : 'foo' } }
const result = allTrue(
foo,
() => foo.a,
() => foo.a.b
)
expect(result).toBeTrue()
})
allType(targetType: RambdaTypes): (...input: any[]) => boolean
It returns a function which will return true if all of its inputs arguments belong to targetType.
:boom:
targetTypeis one of the possible returns ofR.type
const targetType = 'String'
const result = R.allType(
targetType
)('foo', 'bar', 'baz')
// => true
Try this R.allType example in Rambda REPL
import { type } from './type'
export function allType(targetType){
return (...inputs) => {
let counter = 0
while (counter < inputs.length){
if (type(inputs[ counter ]) !== targetType){
return false
}
counter++
}
return true
}
}
import { allType } from './allType'
test('when true', () => {
const result = allType('Array')(
[ 1, 2, 3 ], [], [ null ]
)
expect(result).toBeTrue()
})
test('when false', () => {
const result = allType('String')(
1, undefined, null, []
)
expect(result).toBeFalse()
})
always<T>(x: T): () => T
It returns function that always returns x.
const fn = R.always(7)
console.log(fn())// => 7
Try this R.always example in Rambda REPL
export function always(x){
return () => x
}
import { always } from './always'
import { F } from './F'
test('happy', () => {
const fn = always(7)
expect(fn()).toEqual(7)
expect(fn()).toEqual(7)
})
test('f', () => {
const fn = always(F())
expect(fn()).toBeFalse()
expect(fn()).toBeFalse()
})
and<T, U>(x: T, y: U): T | U
Logical AND
R.and(true, true); // => true
R.and(false, true); // => false
R.and(true, 'foo'); // => 'foo'
Try this R.and example in Rambda REPL
export function and(a, b){
if (arguments.length === 1) return _b => and(a, _b)
return a && b
}
import { and } from './and'
test('happy', () => {
expect(and(1, 'foo')).toBe('foo')
expect(and(true, true)).toBeTrue()
expect(and(true)(true)).toBeTrue()
expect(and(true, false)).toBeFalse()
expect(and(false, true)).toBeFalse()
expect(and(false, false)).toBeFalse()
})
any<T>(predicate: (x: T) => boolean, list: T[]): boolean
It returns true, if at least one member of list returns true, when passed to a predicate function.
const list = [1, 2, 3]
const predicate = x => x * x > 8
R.any(fn, list)
// => true
Try this R.any example in Rambda REPL
export function any(predicate, list){
if (arguments.length === 1) return _list => any(predicate, _list)
let counter = 0
while (counter < list.length){
if (predicate(list[ counter ], counter)){
return true
}
counter++
}
return false
}
import { any } from './any'
const list = [ 1, 2, 3 ]
test('happy', () => {
expect(any(x => x < 0, list)).toBeFalse()
})
test('with curry', () => {
expect(any(x => x > 2)(list)).toBeTrue()
})
anyFalse(...input: any[]): boolean
It returns true if any of inputs is falsy(empty objects and empty arrays are considered falsy).
R.anyFalse(1, {a: 1}, [1], () => false)
// => true
Try this R.anyFalse example in Rambda REPL
import { isFalsy } from './_internals/isFalsy'
import { type } from './type'
export function anyFalse(...inputs){
let counter = 0
while (counter < inputs.length){
const x = inputs[ counter ]
if (type(x) === 'Function'){
if (isFalsy(x())){
return true
}
} else if (isFalsy(x)){
return true
}
counter++
}
return false
}
import { anyFalse } from './anyFalse'
test('when true', () => {
expect(anyFalse(
true, true, false
)).toBeTruthy()
})
test('when false', () => {
expect(anyFalse(true, true)).toBeFalsy()
})
test('supports function', () => {
expect(anyFalse(
true,
() => true,
() => false
)).toBeTruthy()
})
anyPass<T>(predicates: SafePred<T>[]): SafePred<T>
It accepts list of predicates and returns a function. This function with its input will return true, if any of predicates returns true for this input.
const isBig = x => x > 20
const isOdd = x => x % 2 === 1
const input = 11
const fn = R.anyPass(
[isBig, isOdd]
)
const result = fn(input)
// => true
Try this R.anyPass example in Rambda REPL
export function anyPass(predicates){
return input => {
let counter = 0
while (counter < predicates.length){
if (predicates[ counter ](input)){
return true
}
counter++
}
return false
}
}
import { anyPass } from './anyPass'
test('happy', () => {
const rules = [ x => typeof x === 'string', x => x > 10 ]
const predicate = anyPass(rules)
expect(predicate('foo')).toBeTrue()
expect(predicate(6)).toBeFalse()
})
test('happy', () => {
const rules = [ x => typeof x === 'string', x => x > 10 ]
expect(anyPass(rules)(11)).toBeTrue()
expect(anyPass(rules)(undefined)).toBeFalse()
})
const obj = {
a : 1,
b : 2,
}
test('when returns true', () => {
const conditionArr = [ val => val.a === 1, val => val.a === 2 ]
expect(anyPass(conditionArr)(obj)).toBeTrue()
})
test('when returns false + curry', () => {
const conditionArr = [ val => val.a === 2, val => val.b === 3 ]
expect(anyPass(conditionArr)(obj)).toBeFalse()
})
test('happy', () => {
expect(anyPass([])(3)).toEqual(false)
})
anyTrue(...input: any[]): boolean
It returns true if any of inputs arguments are truthy(empty objects and empty arrays are considered falsy).
R.anyTrue(0, null, [], {}, '', () => true)
// => true
Try this R.anyTrue example in Rambda REPL
import { isTruthy } from './_internals/isTruthy'
import { type } from './type'
export function anyTrue(...inputs){
let counter = 0
while (counter < inputs.length){
const x = inputs[ counter ]
if (type(x) === 'Function'){
if (isTruthy(x())){
return true
}
} else if (isTruthy(x)){
return true
}
counter++
}
return false
}
import { anyTrue } from './anyTrue'
test('when true', () => {
expect(anyTrue(
true, true, false
)).toBeTruthy()
})
test('when false', () => {
expect(anyTrue(
false, false, false
)).toBeFalsy()
})
test('supports function', () => {
expect(anyTrue(
false,
false,
false,
() => false,
() => true
)).toBeTruthy()
})
anyType(targetType: RambdaTypes): (...input: any[]) => boolean
It returns a function which will return true if at least one of its inputs arguments belongs to targetType.
targetType is one of the possible returns of R.type
:boom:
targetTypeis one of the possible returns ofR.type
const targetType = 'String'
const result = R.anyType(
targetType
)(1, {}, 'foo')
// => true
Try this R.anyType example in Rambda REPL
import { type } from './type'
export function anyType(targetType){
return (...inputs) => {
let counter = 0
while (counter < inputs.length){
if (type(inputs[ counter ]) === targetType){
return true
}
counter++
}
return false
}
}
import { anyType } from './anyType'
test('when true', () => {
const result = anyType('Array')(
1, undefined, null, []
)
expect(result).toBeTrue()
})
test('when false', () => {
const result = anyType('String')(
1, undefined, null, []
)
expect(result).toBeFalse()
})
append<T>(x: T, list: T[]): T[]
It adds element x at the end of list.
const x = 'foo'
const result = R.append(x, ['bar', 'baz'])
// => ['bar', 'baz', 'foo']
Try this R.append example in Rambda REPL
export function append(x, input){
if (arguments.length === 1) return _input => append(x, _input)
if (typeof input === 'string') return input.split('').concat(x)
const clone = input.slice()
clone.push(x)
return clone
}
import { append } from './append'
test('happy', () => {
expect(append('tests', [ 'write', 'more' ])).toEqual([
'write',
'more',
'tests',
])
})
test('append to empty array', () => {
expect(append('tests')([])).toEqual([ 'tests' ])
})
test('with strings', () => {
expect(append('o', 'fo')).toEqual([ 'f', 'o', 'o' ])
})
applyDiff<Output>(rules: ApplyDiffRule[], obj: object): Output
It changes paths in an object according to a list of operations. Valid operations are add, update and delete. Its use-case is while writing tests and you need to change the test data.
Note, that you cannot use update operation, if the object path is missing in the input object.
Also, you cannot use add operation, if the object path has a value.
const obj = {a: {b:1, c:2}}
const rules = [
{op: 'remove', path: 'a.c'},
{op: 'add', path: 'a.d', value: 4},
{op: 'update', path: 'a.b', value: 2},
]
const result = R.applyDiff(rules, obj)
const expected = {a: {b: 2, d: 4}}
// => `result` is equal to `expected`
Try this R.applyDiff example in Rambda REPL
import { assocPath } from './assocPath'
import { path as pathModule } from './path'
const ALLOWED_OPERATIONS = [ 'remove', 'add', 'update' ]
export function removeAtPath(path, obj){
const p = typeof path === 'string' ? path.split('.') : path
const len = p.length
if (len === 0) return
if (len === 1) return delete obj[ p[ 0 ] ]
if (len === 2) return delete obj[ p[ 0 ] ][ p[ 1 ] ]
if (len === 3) return delete obj[ p[ 0 ] ][ p[ 1 ] ][ p[ 2 ] ]
if (len === 4) return delete obj[ p[ 0 ] ][ p[ 1 ] ][ p[ 2 ] ][ p[ 3 ] ]
if (len === 5) return delete obj[ p[ 0 ] ][ p[ 1 ] ][ p[ 2 ] ][ p[ 3 ] ][ p[ 4 ] ]
if (len === 6){
return delete obj[ p[ 0 ] ][ p[ 1 ] ][ p[ 2 ] ][ p[ 3 ] ][ p[ 4 ] ][ p[ 5 ] ]
}
if (len === 7){
return delete obj[ p[ 0 ] ][ p[ 1 ] ][ p[ 2 ] ][ p[ 3 ] ][ p[ 4 ] ][ p[ 5 ] ][ p[ 6 ] ]
}
if (len === 8){
return delete obj[ p[ 0 ] ][ p[ 1 ] ][ p[ 2 ] ][ p[ 3 ] ][ p[ 4 ] ][ p[ 5 ] ][ p[ 6 ] ][ p[ 7 ] ]
}
if (len === 9){
return delete obj[ p[ 0 ] ][ p[ 1 ] ][ p[ 2 ] ][ p[ 3 ] ][ p[ 4 ] ][ p[ 5 ] ][ p[ 6 ] ][ p[ 7 ] ][ p[ 8 ] ]
}
if (len === 10){
return delete obj[ p[ 0 ] ][ p[ 1 ] ][ p[ 2 ] ][ p[ 3 ] ][ p[ 4 ] ][ p[ 5 ] ][ p[ 6 ] ][ p[ 7 ] ][ p[ 8 ] ][
p[ 9 ]
]
}
}
export function applyDiff(rules, obj){
if (arguments.length === 1) return _obj => applyDiff(rules, _obj)
let clone = { ...obj }
rules.forEach(({ op, path, value }) => {
if (!ALLOWED_OPERATIONS.includes(op)) return
if (op === 'add' && path && value !== undefined){
if (pathModule(path, obj)) return
return clone = assocPath(
path, value, clone
)
}
if (op === 'remove'){
if (pathModule(path, obj) === undefined) return
return removeAtPath(path, clone)
}
if (op === 'update' && path && value !== undefined){
if (pathModule(path, obj) === undefined) return
return clone = assocPath(
path, value, clone
)
}
})
return clone
}
import { applyDiff } from './applyDiff'
test('remove operation', () => {
const rules = [
{
op : 'remove',
path : 'a.b',
},
]
const result = applyDiff(rules, {
a : {
b : 1,
c : 2,
},
})
expect(result).toEqual({ a : { c : 2 } })
})
test('update operation', () => {
const rules = [
{
op : 'update',
path : 'a.b',
value : 3,
},
{
op : 'update',
path : 'a.c.1',
value : 3,
},
{
op : 'update',
path : 'a.d',
value : 3,
},
]
const result = applyDiff(rules, {
a : {
b : 1,
c : [ 1, 2 ],
},
})
expect(result).toEqual({
a : {
b : 3,
c : [ 1, 3 ],
},
})
})
test('add operation', () => {
const rules = [
{
op : 'add',
path : 'a.b',
value : 3,
},
{
op : 'add',
path : 'a.d',
value : 3,
},
]
const result = applyDiff(rules, {
a : {
b : 1,
c : 2,
},
})
expect(result).toEqual({
a : {
b : 1,
c : 2,
d : 3,
},
})
})
applySpec<Spec extends Record<string, (...args: any[]) => any>>(
spec: Spec
): (
...args: Parameters<ValueOfRecord<Spec>>
) => { [Key in keyof Spec]: ReturnType<Spec[Key]> }
:boom: The currying in this function works best with functions with 4 arguments or less. (arity of 4)
const fn = R.applySpec({
sum: R.add,
nested: { mul: R.multiply }
})
const result = fn(2, 4)
// => { sum: 6, nested: { mul: 8 } }
Try this R.applySpec example in Rambda REPL
import { _isArray } from './_internals/_isArray'
// recursively traverse the given spec object to find the highest arity function
function __findHighestArity(spec, max = 0){
for (const key in spec){
if (spec.hasOwnProperty(key) === false || key === 'constructor') continue
if (typeof spec[ key ] === 'object'){
max = Math.max(max, __findHighestArity(spec[ key ]))
}
if (typeof spec[ key ] === 'function'){
max = Math.max(max, spec[ key ].length)
}
}
return max
}
function __filterUndefined(){
const defined = []
let i = 0
const l = arguments.length
while (i < l){
if (typeof arguments[ i ] === 'undefined') break
defined[ i ] = arguments[ i ]
i++
}
return defined
}
function __applySpecWithArity(
spec, arity, cache
){
const remaining = arity - cache.length
if (remaining === 1)
return x =>
__applySpecWithArity(
spec, arity, __filterUndefined(...cache, x)
)
if (remaining === 2)
return (x, y) =>
__applySpecWithArity(
spec, arity, __filterUndefined(
...cache, x, y
)
)
if (remaining === 3)
return (
x, y, z
) =>
__applySpecWithArity(
spec, arity, __filterUndefined(
...cache, x, y, z
)
)
if (remaining === 4)
return (
x, y, z, a
) =>
__applySpecWithArity(
spec,
arity,
__filterUndefined(
...cache, x, y, z, a
)
)
if (remaining > 4)
return (...args) =>
__applySpecWithArity(
spec, arity, __filterUndefined(...cache, ...args)
)
// handle spec as Array
if (_isArray(spec)){
const ret = []
let i = 0
const l = spec.length
for (; i < l; i++){
// handle recursive spec inside array
if (typeof spec[ i ] === 'object' || _isArray(spec[ i ])){
ret[ i ] = __applySpecWithArity(
spec[ i ], arity, cache
)
}
// apply spec to the key
if (typeof spec[ i ] === 'function'){
ret[ i ] = spec[ i ](...cache)
}
}
return ret
}
// handle spec as Object
const ret = {}
// apply callbacks to each property in the spec object
for (const key in spec){
if (spec.hasOwnProperty(key) === false || key === 'constructor') continue
// apply the spec recursively
if (typeof spec[ key ] === 'object'){
ret[ key ] = __applySpecWithArity(
spec[ key ], arity, cache
)
continue
}
// apply spec to the key
if (typeof spec[ key ] === 'function'){
ret[ key ] = spec[ key ](...cache)
}
}
return ret
}
export function applySpec(spec, ...args){
// get the highest arity spec function, cache the result and pass to __applySpecWithArity
const arity = __findHighestArity(spec)
if (arity === 0){
return () => ({})
}
const toReturn = __applySpecWithArity(
spec, arity, args
)
return toReturn
}
import { applySpec as applySpecRamda, nAry } from 'ramda'
import { add, always, compose, dec, inc, map, path, prop, T } from '../rambda'
import { applySpec } from './applySpec'
test('different than Ramda when bad spec', () => {
const result = applySpec({ sum : { a : 1 } })(1, 2)
const ramdaResult = applySpecRamda({ sum : { a : 1 } })(1, 2)
expect(result).toEqual({})
expect(ramdaResult).toEqual({ sum : { a : {} } })
})
test('works with empty spec', () => {
expect(applySpec({})()).toEqual({})
expect(applySpec([])(1, 2)).toEqual({})
expect(applySpec(null)(1, 2)).toEqual({})
})
test('works with unary functions', () => {
const result = applySpec({
v : inc,
u : dec,
})(1)
const expected = {
v : 2,
u : 0,
}
expect(result).toEqual(expected)
})
test('works with binary functions', () => {
const result = applySpec({ sum : add })(1, 2)
expect(result).toEqual({ sum : 3 })
})
test('works with nested specs', () => {
const result = applySpec({
unnested : always(0),
nested : { sum : add },
})(1, 2)
const expected = {
unnested : 0,
nested : { sum : 3 },
}
expect(result).toEqual(expected)
})
test('works with arrays of nested specs', () => {
const result = applySpec({
unnested : always(0),
nested : [ { sum : add } ],
})(1, 2)
expect(result).toEqual({
unnested : 0,
nested : [ { sum : 3 } ],
})
})
test('works with arrays of spec objects', () => {
const result = applySpec([ { sum : add } ])(1, 2)
expect(result).toEqual([ { sum : 3 } ])
})
test('works with arrays of functions', () => {
const result = applySpec([ map(prop('a')), map(prop('b')) ])([
{
a : 'a1',
b : 'b1',
},
{
a : 'a2',
b : 'b2',
},
])
const expected = [
[ 'a1', 'a2' ],
[ 'b1', 'b2' ],
]
expect(result).toEqual(expected)
})
test('works with a spec defining a map key', () => {
expect(applySpec({ map : prop('a') })({ a : 1 })).toEqual({ map : 1 })
})
test('cannot retains the highest arity', () => {
const f = applySpec({
f1 : nAry(2, T),
f2 : nAry(5, T),
})
const fRamda = applySpecRamda({
f1 : nAry(2, T),
f2 : nAry(5, T),
})
expect(f.length).toBe(0)
expect(fRamda.length).toBe(5)
})
test('returns a curried function', () => {
expect(applySpec({ sum : add })(1)(2)).toEqual({ sum : 3 })
})
// Additional tests
// ============================================
test('arity', () => {
const spec = {
one : x1 => x1,
two : (x1, x2) => x1 + x2,
three : (
x1, x2, x3
) => x1 + x2 + x3,
}
expect(applySpec(
spec, 1, 2, 3
)).toEqual({
one : 1,
two : 3,
three : 6,
})
})
test('arity over 5 arguments', () => {
const spec = {
one : x1 => x1,
two : (x1, x2) => x1 + x2,
three : (
x1, x2, x3
) => x1 + x2 + x3,
four : (
x1, x2, x3, x4
) => x1 + x2 + x3 + x4,
five : (
x1, x2, x3, x4, x5
) => x1 + x2 + x3 + x4 + x5,
}
expect(applySpec(
spec, 1, 2, 3, 4, 5
)).toEqual({
one : 1,
two : 3,
three : 6,
four : 10,
five : 15,
})
})
test('curried', () => {
const spec = {
one : x1 => x1,
two : (x1, x2) => x1 + x2,
three : (
x1, x2, x3
) => x1 + x2 + x3,
}
expect(applySpec(spec)(1)(2)(3)).toEqual({
one : 1,
two : 3,
three : 6,
})
})
test('curried over 5 arguments', () => {
const spec = {
one : x1 => x1,
two : (x1, x2) => x1 + x2,
three : (
x1, x2, x3
) => x1 + x2 + x3,
four : (
x1, x2, x3, x4
) => x1 + x2 + x3 + x4,
five : (
x1, x2, x3, x4, x5
) => x1 + x2 + x3 + x4 + x5,
}
expect(applySpec(spec)(1)(2)(3)(4)(5)).toEqual({
one : 1,
two : 3,
three : 6,
four : 10,
five : 15,
})
})
test('undefined property', () => {
const spec = { prop : path([ 'property', 'doesnt', 'exist' ]) }
expect(applySpec(spec, {})).toEqual({ prop : undefined })
})
test('restructure json object', () => {
const spec = {
id : path('user.id'),
name : path('user.firstname'),
profile : path('user.profile'),
doesntExist : path('user.profile.doesntExist'),
info : { views : compose(inc, prop('views')) },
type : always('playa'),
}
const data = {
user : {
id : 1337,
firstname : 'john',
lastname : 'shaft',
profile : 'shaft69',
},
views : 42,
}
expect(applySpec(spec, data)).toEqual({
id : 1337,
name : 'john',
profile : 'shaft69',
doesntExist : undefined,
info : { views : 43 },
type : 'playa',
})
})
assoc<T, U, K extends string>(prop: K, val: T, obj: U): Record<K, T> & U
It makes a shallow clone of obj with setting or overriding the property prop with newValue.
:boom: This copies and flattens prototype properties onto the new object as well. All non-primitive properties are copied by reference.
R.assoc('c', 3, {a: 1, b: 2})
// => {a: 1, b: 2, c: 3}
Try this R.assoc example in Rambda REPL
import { curry } from './curry'
function assocFn(
prop, newValue, obj
){
return Object.assign(
{}, obj, { [ prop ] : newValue }
)
}
export const assoc = curry(assocFn)
import { assoc } from './assoc'
test('adds a key to an empty object', () => {
expect(assoc(
'a', 1, {}
)).toEqual({ a : 1 })
})
test('adds a key to a non-empty object', () => {
expect(assoc(
'b', 2, { a : 1 }
)).toEqual({
a : 1,
b : 2,
})
})
test('adds a key to a non-empty object - curry case 1', () => {
expect(assoc('b', 2)({ a : 1 })).toEqual({
a : 1,
b : 2,
})
})
test('adds a key to a non-empty object - curry case 2', () => {
expect(assoc('b')(2, { a : 1 })).toEqual({
a : 1,
b : 2,
})
})
test('adds a key to a non-empty object - curry case 3', () => {
const result = assoc('b')(2)({ a : 1 })
expect(result).toEqual({
a : 1,
b : 2,
})
})
test('changes an existing key', () => {
expect(assoc(
'a', 2, { a : 1 }
)).toEqual({ a : 2 })
})
test('undefined is considered an empty object', () => {
expect(assoc(
'a', 1, undefined
)).toEqual({ a : 1 })
})
test('null is considered an empty object', () => {
expect(assoc(
'a', 1, null
)).toEqual({ a : 1 })
})
test('value can be null', () => {
expect(assoc(
'a', null, null
)).toEqual({ a : null })
})
test('value can be undefined', () => {
expect(assoc(
'a', undefined, null
)).toEqual({ a : undefined })
})
test('assignment is shallow', () => {
expect(assoc(
'a', { b : 2 }, { a : { c : 3 } }
)).toEqual({ a : { b : 2 } })
})
assocPath<Output>(path: Path, newValue: any, obj: object): Output
It makes a shallow clone of obj with setting or overriding with newValue the property found with path.
const path = 'b.c'
const newValue = 2
const obj = { a: 1 }
R.assocPath(path, newValue, obj)
// => { a : 1, b : { c : 2 }}
Try this R.assocPath example in Rambda REPL
import { _isArray } from './_internals/_isArray'
import { _isInteger } from './_internals/_isInteger'
import { assoc } from './assoc'
import { curry } from './curry'
function assocPathFn(
path, newValue, input
){
const pathArrValue =
typeof path === 'string' ?
path.split('.').map(x => _isInteger(Number(x)) ? Number(x) : x) :
path
if (pathArrValue.length === 0){
return newValue
}
const index = pathArrValue[ 0 ]
if (pathArrValue.length > 1){
const condition =
typeof input !== 'object' ||
input === null ||
!input.hasOwnProperty(index)
const nextinput = condition ?
_isInteger(pathArrValue[ 1 ]) ?
[] :
{} :
input[ index ]
newValue = assocPathFn(
Array.prototype.slice.call(pathArrValue, 1),
newValue,
nextinput
)
}
if (_isInteger(index) && _isArray(input)){
const arr = input.slice()
arr[ index ] = newValue
return arr
}
return assoc(
index, newValue, input
)
}
export const assocPath = curry(assocPathFn)
import { assocPath } from './assocPath'
test('string can be used as path input', () => {
const testObj = {
a : [ { b : 1 }, { b : 2 } ],
d : 3,
}
const result = assocPath(
'a.0.b', 10, testObj
)
const expected = {
a : [ { b : 10 }, { b : 2 } ],
d : 3,
}
expect(result).toEqual(expected)
})
test('bug', () => {
/*
https://github.com/selfrefactor/rambda/issues/524
*/
const state = {}
const withDateLike = assocPath(
[ 'outerProp', '2020-03-10' ],
{ prop : 2 },
state
)
const withNumber = assocPath(
[ 'outerProp', '5' ], { prop : 2 }, state
)
const withDateLikeExpected = { outerProp : { '2020-03-10' : { prop : 2 } } }
const withNumberExpected = { outerProp : { 5 : { prop : 2 } } }
expect(withDateLike).toEqual(withDateLikeExpected)
expect(withNumber).toEqual(withNumberExpected)
})
test('adds a key to an empty object', () => {
expect(assocPath(
[ 'a' ], 1, {}
)).toEqual({ a : 1 })
})
test('adds a key to a non-empty object', () => {
expect(assocPath(
'b', 2, { a : 1 }
)).toEqual({
a : 1,
b : 2,
})
})
test('adds a nested key to a non-empty object', () => {
expect(assocPath(
'b.c', 2, { a : 1 }
)).toEqual({
a : 1,
b : { c : 2 },
})
})
test('adds a nested key to a nested non-empty object - curry case 1', () => {
expect(assocPath('b.d',
3)({
a : 1,
b : { c : 2 },
})).toEqual({
a : 1,
b : {
c : 2,
d : 3,
},
})
})
test('adds a key to a non-empty object - curry case 1', () => {
expect(assocPath('b', 2)({ a : 1 })).toEqual({
a : 1,
b : 2,
})
})
test('adds a nested key to a non-empty object - curry case 1', () => {
expect(assocPath('b.c', 2)({ a : 1 })).toEqual({
a : 1,
b : { c : 2 },
})
})
test('adds a key to a non-empty object - curry case 2', () => {
expect(assocPath('b')(2, { a : 1 })).toEqual({
a : 1,
b : 2,
})
})
test('adds a key to a non-empty object - curry case 3', () => {
const result = assocPath('b')(2)({ a : 1 })
expect(result).toEqual({
a : 1,
b : 2,
})
})
test('changes an existing key', () => {
expect(assocPath(
'a', 2, { a : 1 }
)).toEqual({ a : 2 })
})
test('undefined is considered an empty object', () => {
expect(assocPath(
'a', 1, undefined
)).toEqual({ a : 1 })
})
test('null is considered an empty object', () => {
expect(assocPath(
'a', 1, null
)).toEqual({ a : 1 })
})
test('value can be null', () => {
expect(assocPath(
'a', null, null
)).toEqual({ a : null })
})
test('value can be undefined', () => {
expect(assocPath(
'a', undefined, null
)).toEqual({ a : undefined })
})
test('assignment is shallow', () => {
expect(assocPath(
'a', { b : 2 }, { a : { c : 3 } }
)).toEqual({ a : { b : 2 } })
})
test('empty array as path', () => {
const result = assocPath(
[], 3, {
a : 1,
b : 2,
}
)
expect(result).toEqual(3)
})
test('happy', () => {
const expected = { foo : { bar : { baz : 42 } } }
const result = assocPath(
[ 'foo', 'bar', 'baz' ], 42, { foo : null }
)
expect(result).toEqual(expected)
})
both(pred1: Pred, pred2: Pred): Pred
It returns a function with input argument.
This function will return true, if both firstCondition and secondCondition return true when input is passed as their argument.
const firstCondition = x => x > 10
const secondCondition = x => x < 20
const fn = R.both(secondCondition)
const result = [fn(15), fn(30)]
// => [true, false]
Try this R.both example in Rambda REPL
export function both(f, g){
if (arguments.length === 1) return _g => both(f, _g)
return (...input) => f(...input) && g(...input)
}
import { both } from './both'
const firstFn = val => val > 0
const secondFn = val => val < 10
test('with curry', () => {
expect(both(firstFn)(secondFn)(17)).toBeFalse()
})
test('without curry', () => {
expect(both(firstFn, secondFn)(7)).toBeTrue()
})
test('with multiple inputs', () => {
const between = function (
a, b, c
){
return a < b && b < c
}
const total20 = function (
a, b, c
){
return a + b + c === 20
}
const fn = both(between, total20)
expect(fn(
5, 7, 8
)).toBeTrue()
})
test('skip evaluation of the second expression', () => {
let effect = 'not evaluated'
const F = function (){
return false
}
const Z = function (){
effect = 'Z got evaluated'
}
both(F, Z)()
expect(effect).toBe('not evaluated')
})
chain<T, U>(fn: (n: T) => U[], list: T[]): U[]
The method is also known as flatMap.
const duplicate = n => [ n, n ]
const list = [ 1, 2, 3 ]
const result = chain(duplicate, list)
// => [ 1, 1, 2, 2, 3, 3 ]
Try this R.chain example in Rambda REPL
export function chain(fn, list){
if (arguments.length === 1){
return _list => chain(fn, _list)
}
return [].concat(...list.map(fn))
}
import { chain } from './chain'
const duplicate = n => [ n, n ]
test('happy', () => {
const fn = x => [ x * 2 ]
const list = [ 1, 2, 3 ]
const result = chain(fn, list)
expect(result).toEqual([ 2, 4, 6 ])
})
test('maps then flattens one level', () => {
expect(chain(duplicate, [ 1, 2, 3 ])).toEqual([ 1, 1, 2, 2, 3, 3 ])
})
test('maps then flattens one level - curry', () => {
expect(chain(duplicate)([ 1, 2, 3 ])).toEqual([ 1, 1, 2, 2, 3, 3 ])
})
test('flattens only one level', () => {
const nest = n => [ [ n ] ]
expect(chain(nest, [ 1, 2, 3 ])).toEqual([ [ 1 ], [ 2 ], [ 3 ] ])
})
clamp(min: number, max: number, input: number): number
Restrict a number input to be within min and max limits.
If input is bigger than max, then the result is max.
If input is smaller than min, then the result is min.
const result = [
R.clamp(0, 10, 5),
R.clamp(0, 10, -1),
R.clamp(0, 10, 11)
]
// => [5, 0, 10]
Try this R.clamp example in Rambda REPL
import { curry } from './curry'
function clampFn(
min, max, input
){
if (min > max){
throw new Error('min must not be greater than max in clamp(min, max, value)')
}
if (input >= min && input <= max) return input
if (input > max) return max
if (input < min) return min
}
export const clamp = curry(clampFn)
import { clamp } from './clamp'
test('when min is greater than max', () => {
expect(() => clamp(
-5, -10, 5
)).toThrowWithMessage(Error,
'min must not be greater than max in clamp(min, max, value)')
})
test('rambda specs', () => {
expect(clamp(
1, 10, 0
)).toEqual(1)
expect(clamp(
3, 12, 1
)).toEqual(3)
expect(clamp(
-15, 3, -100
)).toEqual(-15)
expect(clamp(
1, 10, 20
)).toEqual(10)
expect(clamp(
3, 12, 23
)).toEqual(12)
expect(clamp(
-15, 3, 16
)).toEqual(3)
expect(clamp(
1, 10, 4
)).toEqual(4)
expect(clamp(
3, 12, 6
)).toEqual(6)
expect(clamp(
-15, 3, 0
)).toEqual(0)
})
clone<T>(input: T): T
It creates a deep copy of the input, which may contain (nested) Arrays and Objects, Numbers, Strings, Booleans and Dates.
const objects = [{a: 1}, {b: 2}];
const objectsClone = R.clone(objects);
const result = [
R.equals(objects, objectsClone),
R.equals(objects[0], objectsClone[0]),
] // => [ true, true ]
Try this R.clone example in Rambda REPL
import { _isArray } from './_internals/_isArray'
export function clone(input){
const out = _isArray(input) ? Array(input.length) : {}
if (input && input.getTime) return new Date(input.getTime())
for (const key in input){
const v = input[ key ]
out[ key ] =
typeof v === 'object' && v !== null ?
v.getTime ?
new Date(v.getTime()) :
clone(v) :
v
}
return out
}
import assert from 'assert'
import { clone } from './clone'
import { equals } from './equals'
test('with array', () => {
const arr = [
{
b : 2,
c : 'foo',
d : [ 1, 2, 3 ],
},
1,
new Date(),
null,
]
expect(clone(arr)).toEqual(arr)
})
test('with object', () => {
const obj = {
a : 1,
b : 2,
c : 3,
d : [ 1, 2, 3 ],
e : new Date(),
}
expect(clone(obj)).toEqual(obj)
})
test('with date', () => {
const date = new Date(
2014, 10, 14, 23, 59, 59, 999
)
const cloned = clone(date)
assert.notStrictEqual(date, cloned)
expect(cloned).toEqual(new Date(
2014, 10, 14, 23, 59, 59, 999
))
expect(cloned.getDay()).toEqual(5)
})
test('with R.equals', () => {
const objects = [ { a : 1 }, { b : 2 } ]
const objectsClone = clone(objects)
const result = [
equals(objects, objectsClone),
equals(objects[ 0 ], objectsClone[ 0 ]),
]
expect(result).toEqual([ true, true ])
})
complement<T extends any[]>(pred: (...args: T) => boolean): (...args: T) => boolean
It returns inverted version of origin function that accept input as argument.
The return value of inverted is the negative boolean value of origin(input).
const origin = x => x > 5
const inverted = complement(origin)
const result = [
origin(7),
inverted(7)
] => [ true, false ]
Try this R.complement example in Rambda REPL
export function complement(fn){
return (...input) => !fn(...input)
}
import { complement } from './complement'
test('happy', () => {
const fn = complement(x => x.length === 0)
expect(fn([ 1, 2, 3 ])).toBeTrue()
})
test('with multiple parameters', () => {
const between = function (
a, b, c
){
return a < b && b < c
}
const f = complement(between)
expect(f(
4, 5, 11
)).toEqual(false)
expect(f(
12, 2, 6
)).toEqual(true)
})
It performs right-to-left function composition.
const result = R.compose(
R.map(x => x * 2),
R.filter(x => x > 2)
)([1, 2, 3, 4])
// => [6, 8]
Try this R.compose example in Rambda REPL
composeAsync<Out>(
...fns: (Async<any> | Func<any>)[]
): (input: any) => Promise<Out>
Asynchronous version of R.compose
:boom: It doesn't work with promises or function returning promises such as
const foo = input => new Promise(...).
const add = async x => {
await R.delay(100)
return x + 1
}
const multiply = async x => {
await R.delay(100)
return x * 2
}
const result = await R.composeAsync(
add,
multiply
)(1)
// `result` resolves to `3`
Try this R.composeAsync example in Rambda REPL
import { type } from './type'
export function composeAsync(...inputArguments){
return async function (startArgument){
let argumentsToPass = startArgument
while (inputArguments.length !== 0){
const fn = inputArguments.pop()
const typeFn = type(fn)
if (typeFn === 'Async'){
argumentsToPass = await fn(argumentsToPass)
} else {
argumentsToPass = fn(argumentsToPass)
if (type(argumentsToPass) === 'Promise'){
argumentsToPass = await argumentsToPass
}
}
}
return argumentsToPass
}
}
import { composeAsync } from './composeAsync'
import { delay } from './delay'
async function identity(x){
await delay(100)
return x
}
test('happy', async () => {
const fn1 = async x => {
await delay(100)
return x.map(xx => xx + 1)
}
const fn2 = async x => {
await delay(100)
return x.map(xx => xx * 2)
}
const result = await composeAsync(fn1,
fn2)(await Promise.all([ identity(1), identity(2), identity(3) ]))
expect(result).toEqual([ 3, 5, 7 ])
})
const delayFn = ms =>
new Promise(resolve => {
resolve(ms + 1)
})
test('with function returning promise', async () => {
const result = await composeAsync(
x => x,
x => x + 1,
delayFn,
x => x
)(1)
expect(result).toEqual(3)
})
test('throw error', async () => {
const fn = async () => {
await delay(1)
JSON.parse('{foo')
}
let didThrow = false
try {
await composeAsync(fn, x => x + 1)(20)
} catch (e){
didThrow = true
}
expect(didThrow).toBeTrue()
})
concat<T>(x: T[], y: T[]): T[]
It returns a new string or array, which is the result of merging x and y.
R.concat([1, 2])([3, 4]) // => [1, 2, 3, 4]
R.concat('foo', 'bar') // => 'foobar'
Try this R.concat example in Rambda REPL
export function concat(x, y){
if (arguments.length === 1) return _y => concat(x, _y)
return typeof x === 'string' ? `${ x }${ y }` : [ ...x, ...y ]
}
import { concat } from './concat'
test('happy', () => {
const arr1 = [ 'a', 'b', 'c' ]
const arr2 = [ 'd', 'e', 'f' ]
const a = concat(arr1, arr2)
const b = concat(arr1)(arr2)
const expectedResult = [ 'a', 'b', 'c', 'd', 'e', 'f' ]
expect(a).toEqual(expectedResult)
expect(b).toEqual(expectedResult)
})
test('with strings', () => {
expect(concat('ABC', 'DEF')).toEqual('ABCDEF')
})
cond(conditions: ([Pred, (...a: any[]) => any])[]): (...x: any[]) => any
It takes list with conditions and returns a new function fn that expects input as argument.
This function will start evaluating the conditions in order to find the first winner(order of conditions matter).
The winner is this condition, which left side returns true when input is its argument. Then the evaluation of the right side of the winner will be the final result.
If no winner is found, then fn returns undefined.
const fn = R.cond([
[ x => x > 25, R.always('more than 25') ],
[ x => x > 15, R.always('more than 15') ],
[ R.T, x => `${x} is nothing special` ],
])
const result = [
fn(30),
fn(20),
fn(10),
]
// => ['more than 25', 'more than 15', '10 is nothing special']
Try this R.cond example in Rambda REPL
export function cond(conditions){
return input => {
let done = false
let toReturn
conditions.forEach(([ predicate, resultClosure ]) => {
if (!done && predicate(input)){
done = true
toReturn = resultClosure(input)
}
})
return toReturn
}
}
import { always } from './always'
import { cond } from './cond'
import { equals } from './equals'
import { T } from './T'
test('returns a function', () => {
expect(typeof cond([])).toEqual('function')
})
test('returns a conditional function', () => {
const fn = cond([
[ equals(0), always('water freezes at 0°C') ],
[ equals(100), always('water boils at 100°C') ],
[
T,
function (temp){
return 'nothing special happens at ' + temp + '°C'
},
],
])
expect(fn(0)).toEqual('water freezes at 0°C')
expect(fn(50)).toEqual('nothing special happens at 50°C')
expect(fn(100)).toEqual('water boils at 100°C')
})
test('no winner', () => {
const fn = cond([
[ equals('foo'), always(1) ],
[ equals('bar'), always(2) ],
])
expect(fn('quux')).toEqual(undefined)
})
test('predicates are tested in order', () => {
const fn = cond([
[ T, always('foo') ],
[ T, always('bar') ],
[ T, always('baz') ],
])
expect(fn()).toEqual('foo')
})
converge(after: ((...a: any[]) => any), fns: ((...x: any[]) => any)[]): (...y: any[]) => any
Accepts a converging function and a list of branching functions and returns a new function. When invoked, this new function is applied to some arguments, each branching function is applied to those same arguments. The results of each branching function are passed as arguments to the converging function to produce the return value.
:boom: Explanation is taken from
Ramdadocumentation
const result = R.converge(R.multiply)([ R.add(1), R.add(3) ])(2)
// => 15
Try this R.converge example in Rambda REPL
import { curryN } from './curryN'
import { map } from './map'
import { max } from './max'
import { reduce } from './reduce'
export function converge(fn, transformers){
if (arguments.length === 1)
return _transformers => converge(fn, _transformers)
const highestArity = reduce(
(a, b) => max(a, b.length), 0, transformers
)
return curryN(highestArity, function (){
return fn.apply(this,
map(g => g.apply(this, arguments), transformers))
})
}
import { add } from './add'
import { converge } from './converge'
import { multiply } from './multiply'
const f1 = converge(multiply, [ a => a + 1, a => a + 10 ])
const f2 = converge(multiply, [ a => a + 1, (a, b) => a + b + 10 ])
const f3 = converge(multiply, [ a => a + 1, (
a, b, c
) => a + b + c + 10 ])
test('happy', () => {
expect(f2(6, 7)).toEqual(161)
})
test('passes the results of applying the arguments individually', () => {
const result = converge(multiply)([ add(1), add(3) ])(2)
expect(result).toEqual(15)
})
test('returns a function with the length of the longest argument', () => {
expect(f1.length).toEqual(1)
expect(f2.length).toEqual(2)
expect(f3.length).toEqual(3)
})
test('passes context to its functions', () => {
const a = function (x){
return this.f1(x)
}
const b = function (x){
return this.f2(x)
}
const c = function (x, y){
return this.f3(x, y)
}
const d = converge(c, [ a, b ])
const context = {
f1 : add(1),
f2 : add(2),
f3 : add,
}
expect(a.call(context, 1)).toEqual(2)
expect(b.call(context, 1)).toEqual(3)
expect(d.call(context, 1)).toEqual(5)
})
test('works with empty functions list', () => {
const fn = converge(function (){
return arguments.length
}, [])
expect(fn.length).toEqual(0)
expect(fn()).toEqual(0)
})
count<T>(searchFor: T, list: any[]): number
It counts how many times searchFor is within list according to R.equals.
const list = [1, {a:1}, 1, 'foo']
const searchFor = 1
const result = R.count(searchFor, list)
// => 2
Try this R.count example in Rambda REPL
import { _isArray } from './_internals/_isArray'
import { equals } from './equals'
export function count(searchFor, list){
if (arguments.length === 1){
return _list => count(searchFor, _list)
}
if (!_isArray(list)) return 0
return list.filter(x => equals(x, searchFor)).length
}
import { count } from './count'
test('when 0', () => {
const target = { a : 1 }
const list = []
const result = count(target, list)
const expectedResult = 0
expect(result).toEqual(expectedResult)
})
test('when 2', () => {
const target = { a : 1 }
const list = [ 2, 1, 2, { a : 1 }, 22, { a : 1 } ]
const result = count(target)(list)
const expectedResult = 2
expect(result).toEqual(expectedResult)
})
It expects a function as input and returns its curried version.
const fn = (a, b, c) => a + b + c
const curried = R.curry(fn)
const sum = curried(1,2)
const result = sum(3) // => 6
Try this R.curry example in Rambda REPL
It returns a curried equivalent of the provided function, with the specified arity.
debounce<T, U>(fn: (input: T) => U, ms: number): (input: T) => U
It creates a debounced function that delays invoking fn until after wait milliseconds ms have elapsed since the last time the debounced function was invoked.
:boom: Description is taken from
Lodashdocs
let counter = 0
const increment = () => {
counter++
}
const debounced = R.debounce(increment, 1000)
const result = async function(){
debounced()
await R.delay(500)
debounced()
await R.delay(800)
console.log(counter) // => 0
await R.delay(1200)
console.log(counter) // => 1
return counter
}
// `result` resolves to `1`
Try this R.debounce example in Rambda REPL
export function debounce(
func, ms, immediate = false
){
let timeout
return function (...input){
const later = function (){
timeout = null
if (!immediate){
func.apply(null, input)
}
}
const callNow = immediate && !timeout
clearTimeout(timeout)
timeout = setTimeout(later, ms)
if (callNow){
func.apply(null, input)
}
}
}
import { debounce } from './debounce'
import { delay } from './delay'
test('happy', async () => {
let counter = 0
let aHolder
let bHolder
const inc = (a, b) => {
aHolder = a
bHolder = b
counter++
}
const incWrapped = debounce(inc, 500)
incWrapped(1, 2)
expect(counter).toBe(0)
expect(aHolder).toBe(undefined)
expect(bHolder).toBe(undefined)
await delay(200)
incWrapped(2, 3)
expect(counter).toBe(0)
await delay(200)
incWrapped(3, 4)
expect(counter).toBe(0)
expect(aHolder).toBe(undefined)
expect(bHolder).toBe(undefined)
await delay(200)
incWrapped(5, 6)
expect(counter).toBe(0)
await delay(700)
expect(counter).toBe(1)
expect(aHolder).toBe(5)
expect(bHolder).toBe(6)
})
test('immediate debounce', async () => {
let counter = 0
const inc = () => {
counter++
}
const incWrapped = debounce(
inc, 500, true
)
incWrapped()
expect(counter).toBe(1)
await delay(200)
incWrapped()
expect(counter).toBe(1)
await delay(200)
incWrapped()
expect(counter).toBe(1)
await delay(700)
incWrapped()
expect(counter).toBe(2)
})
It decrements a number.
defaultTo<T>(defaultValue: T, input: T | null | undefined): T
It returns defaultValue, if all of inputArguments are undefined, null or NaN.
Else, it returns the first truthy inputArguments instance(from left to right).
:boom: Rambda's defaultTo accept indefinite number of arguments when non curried, i.e.
R.defaultTo(2, foo, bar, baz).
R.defaultTo('foo', 'bar') // => 'bar'
R.defaultTo('foo', undefined) // => 'foo'
// Important - emtpy string is not falsy value(same as Ramda)
R.defaultTo('foo', '') // => 'foo'
Try this R.defaultTo example in Rambda REPL
function isFalsy(input){
return (
input === undefined ||
input === null ||
Number.isNaN(input) === true
)
}
export function defaultTo(defaultArgument, input){
if (arguments.length === 1){
return _input =>
defaultTo(defaultArgument, _input)
}
return isFalsy(input) ? defaultArgument : input
}
import { defaultTo } from './defaultTo'
test('with undefined', () => {
expect(defaultTo('foo')(undefined)).toEqual('foo')
})
test('with null', () => {
expect(defaultTo('foo')(null)).toEqual('foo')
})
test('with NaN', () => {
expect(defaultTo('foo')(NaN)).toEqual('foo')
})
test('with empty string', () => {
expect(defaultTo('foo', '')).toEqual('')
})
test('with false', () => {
expect(defaultTo('foo', false)).toEqual(false)
})
test('when inputArgument passes initial check', () => {
expect(defaultTo('foo', 'bar')).toEqual('bar')
})
delay(ms: number): Promise<'RAMBDAX_DELAY'>
setTimeout as a promise that resolves to R.DELAY variable after ms milliseconds.
const result = R.delay(1000)
// `result` resolves to `RAMBDAX_DELAY`
Try this R.delay example in Rambda REPL
export const DELAY = 'RAMBDAX_DELAY'
export function delay(ms){
return new Promise(resolve => {
setTimeout(() => {
resolve(DELAY)
}, ms)
})
}
import { DELAY, delay } from './delay'
test('usage with variables', async () => {
expect(await delay(500)).toBe(DELAY)
})
difference<T>(a: T[], b: T[]): T[]
It returns the uniq set of all elements in the first list a not contained in the second list b.
R.equals is used to determine equality.
const a = [ 1, 2, 3, 4 ]
const b = [ 3, 4, 5, 6 ]
const result = difference(a, b)
// => [ 1, 2 ]
Try this R.difference example in Rambda REPL
import { includes } from './includes'
import { uniq } from './uniq'
export function difference(a, b){
if (arguments.length === 1) return _b => difference(a, _b)
return uniq(a).filter(aInstance => !includes(aInstance, b))
}
import { difference } from './difference'
test('difference', () => {
const a = [ 1, 2, 3, 4 ]
const b = [ 3, 4, 5, 6 ]
expect(difference(a)(b)).toEqual([ 1, 2 ])
expect(difference([], [])).toEqual([])
})
test('difference with objects', () => {
const a = [ { id : 1 }, { id : 2 }, { id : 3 }, { id : 4 } ]
const b = [ { id : 3 }, { id : 4 }, { id : 5 }, { id : 6 } ]
expect(difference(a, b)).toEqual([ { id : 1 }, { id : 2 } ])
})
test('no duplicates in first list', () => {
const M2 = [ 1, 2, 3, 4, 1, 2, 3, 4 ]
const N2 = [ 3, 3, 4, 4, 5, 5, 6, 6 ]
expect(difference(M2, N2)).toEqual([ 1, 2 ])
})
test('should use R.equals', () => {
expect(difference([ NaN ], [ NaN ]).length).toEqual(0)
})
It returns a new object that does not contain property prop.
R.dissoc('b', {a: 1, b: 2, c: 3})
// => {a: 1, c: 3}
Try this R.dissoc example in Rambda REPL
R.divide(71, 100) // => 0.71
Try this R.divide example in Rambda REPL
drop<T>(howMany: number, input: T[]): T[]
It returns howMany items dropped from beginning of list or string input.
R.drop(2, ['foo', 'bar', 'baz']) // => ['baz']
R.drop(2, 'foobar') // => 'obar'
Try this R.drop example in Rambda REPL
export function drop(howManyToDrop, listOrString){
if (arguments.length === 1) return _list => drop(howManyToDrop, _list)
return listOrString.slice(howManyToDrop > 0 ? howManyToDrop : 0)
}
import assert from 'assert'
import { drop } from './drop'
test('with array', () => {
expect(drop(2)([ 'foo', 'bar', 'baz' ])).toEqual([ 'baz' ])
expect(drop(3, [ 'foo', 'bar', 'baz' ])).toEqual([])
expect(drop(4, [ 'foo', 'bar', 'baz' ])).toEqual([])
})
test('with string', () => {
expect(drop(3, 'rambda')).toEqual('bda')
})
test('with non-positive count', () => {
expect(drop(0, [ 1, 2, 3 ])).toEqual([ 1, 2, 3 ])
expect(drop(-1, [ 1, 2, 3 ])).toEqual([ 1, 2, 3 ])
expect(drop(-Infinity, [ 1, 2, 3 ])).toEqual([ 1, 2, 3 ])
})
test('should return copy', () => {
const xs = [ 1, 2, 3 ]
assert.notStrictEqual(drop(0, xs), xs)
assert.notStrictEqual(drop(-1, xs), xs)
})
dropLast<T>(howMany: number, input: T[]): T[]
It returns howMany items dropped from the end of list or string input.
R.dropLast(2, ['foo', 'bar', 'baz']) // => ['foo']
R.dropLast(2, 'foobar') // => 'foob'
Try this R.dropLast example in Rambda REPL
export function dropLast(howManyToDrop, listOrString){
if (arguments.length === 1){
return _listOrString => dropLast(howManyToDrop, _listOrString)
}
return howManyToDrop > 0 ?
listOrString.slice(0, -howManyToDrop) :
listOrString.slice()
}
import assert from 'assert'
import { dropLast } from './dropLast'
test('with array', () => {
expect(dropLast(2)([ 'foo', 'bar', 'baz' ])).toEqual([ 'foo' ])
expect(dropLast(3, [ 'foo', 'bar', 'baz' ])).toEqual([])
expect(dropLast(4, [ 'foo', 'bar', 'baz' ])).toEqual([])
})
test('with string', () => {
expect(dropLast(3, 'rambda')).toEqual('ram')
})
test('with non-positive count', () => {
expect(dropLast(0, [ 1, 2, 3 ])).toEqual([ 1, 2, 3 ])
expect(dropLast(-1, [ 1, 2, 3 ])).toEqual([ 1, 2, 3 ])
expect(dropLast(-Infinity, [ 1, 2, 3 ])).toEqual([ 1, 2, 3 ])
})
test('should return copy', () => {
const xs = [ 1, 2, 3 ]
assert.notStrictEqual(dropLast(0, xs), xs)
assert.notStrictEqual(dropLast(-1, xs), xs)
})
const list = [1, 2, 3, 4, 5];
const predicate = x => x >= 3
const result = dropLastWhile(predicate, list);
// => [1, 2]
Try this R.dropLastWhile example in Rambda REPL
dropRepeats<T>(list: T[]): T[]
It removes any successive duplicates according to R.equals.
const result = R.dropRepeats([
1,
1,
{a: 1},
{a:1},
1
])
// => [1, {a: 1}, 1]
Try this R.dropRepeats example in Rambda REPL
import { _isArray } from './_internals/_isArray'
import { equals } from './equals'
export function dropRepeats(list){
if (!_isArray(list)){
throw new Error(`${ list } is not a list`)
}
const toReturn = []
list.reduce((prev, current) => {
if (!equals(prev, current)){
toReturn.push(current)
}
return current
}, undefined)
return toReturn
}
import { dropRepeats as dropRepeatsRamda } from 'ramda'
import { compareCombinations } from './_internals/testUtils'
import { add } from './add'
import { dropRepeats } from './dropRepeats'
const list = [ 1, 2, 2, 2, 3, 4, 4, 5, 5, 3, 2, 2, { a : 1 }, { a : 1 } ]
const listClean = [ 1, 2, 3, 4, 5, 3, 2, { a : 1 } ]
test('happy', () => {
const result = dropRepeats(list)
expect(result).toEqual(listClean)
})
const possibleLists = [
[ add(1), async () => {}, [ 1 ], [ 1 ], [ 2 ], [ 2 ] ],
[ add(1), add(1), add(2) ],
[],
1,
/foo/g,
Promise.resolve(1),
]
describe('brute force', () => {
compareCombinations({
firstInput : possibleLists,
callback : errorsCounters => {
expect(errorsCounters).toMatchInlineSnapshot(`
Object {
"ERRORS_MESSAGE_MISMATCH": 0,
"ERRORS_TYPE_MISMATCH": 0,
"RESULTS_MISMATCH": 1,
"SHOULD_NOT_THROW": 3,
"SHOULD_THROW": 0,
}
`)
},
fn : dropRepeats,
fnRamda : dropRepeatsRamda,
})
})
const list = [{a:1,b:2}, {a:1,b:3}, {a:2, b:4}]
const result = R.dropRepeatsWith(R.prop('a'))
// => [{a:1,b:2}, {a:2, b:4}]
Try this R.dropRepeatsWith example in Rambda REPL
const list = [1, 2, 3, 4]
const predicate = x => x < 3
const result = R.dropWhile(predicate, list)
// => [3, 4]
Try this R.dropWhile example in Rambda REPL
either(firstPredicate: Pred, secondPredicate: Pred): Pred
It returns a new predicate function from firstPredicate and secondPredicate inputs.
This predicate function will return true, if any of the two input predicates return true.
const firstPredicate = x => x > 10
const secondPredicate = x => x % 2 === 0
const predicate = R.either(firstPredicate, secondPredicate)
const result = [
predicate(15),
predicate(8),
predicate(7),
]
// => [true, true, false]
Try this R.either example in Rambda REPL
export function either(firstPredicate, secondPredicate){
if (arguments.length === 1){
return _secondPredicate => either(firstPredicate, _secondPredicate)
}
return (...input) =>
Boolean(firstPredicate(...input) || secondPredicate(...input))
}
import { either } from './either'
test('with multiple inputs', () => {
const between = function (
a, b, c
){
return a < b && b < c
}
const total20 = function (
a, b, c
){
return a + b + c === 20
}
const fn = either(between, total20)
expect(fn(
7, 8, 5
)).toBeTrue()
})
test('skip evaluation of the second expression', () => {
let effect = 'not evaluated'
const F = function (){
return true
}
const Z = function (){
effect = 'Z got evaluated'
}
either(F, Z)()
expect(effect).toBe('not evaluated')
})
test('case 1', () => {
const firstFn = val => val > 0
const secondFn = val => val * 5 > 10
expect(either(firstFn, secondFn)(1)).toBeTrue()
})
test('case 2', () => {
const firstFn = val => val > 0
const secondFn = val => val === -10
const fn = either(firstFn)(secondFn)
expect(fn(-10)).toBeTrue()
})
endsWith(target: string, str: string): boolean
Curried version of String.prototype.endsWith
:boom: It doesn't work with arrays unlike its corresponding Ramda method.
const str = 'foo-bar'
const target = '-bar'
const result = R.endsWith(target, str)
// => true
Try this R.endsWith example in Rambda REPL
export function endsWith(target, str){
if (arguments.length === 1) return _str => endsWith(target, _str)
return str.endsWith(target)
}
import { endsWith } from './endsWith'
test('happy', () => {
expect(endsWith('bar', 'foo-bar')).toBeTrue()
expect(endsWith('baz')('foo-bar')).toBeFalse()
})
test('does not work with arrays', () => {
expect(() => endsWith([ 'c' ], [ 'a', 'b', 'c' ])).toThrowWithMessage(Error,
'str.endsWith is not a function')
})
It returns true if property prop in obj1 is equal to property prop in obj2 according to R.equals.
const obj1 = {a: 1, b:2}
const obj2 = {a: 1, b:3}
const result = R.eqProps('a', obj1, obj2)
// => true
Try this R.eqProps example in Rambda REPL
equals<T>(x: T, y: T): boolean
It deeply compares x and y and returns true if they are equal.
:boom: It doesn't handle cyclical data structures and functions
R.equals(
[1, {a:2}, [{b: 3}]],
[1, {a:2}, [{b: 3}]]
) // => true
Try this R.equals example in Rambda REPL
import { type } from './type'
function parseError(maybeError){
const typeofError = maybeError.__proto__.toString()
if (![ 'Error', 'TypeError' ].includes(typeofError)) return []
return [ typeofError, maybeError.message ]
}
function parseDate(maybeDate){
if (!maybeDate.toDateString) return [ false ]
return [ true, maybeDate.getTime() ]
}
function parseRegex(maybeRegex){
if (maybeRegex.constructor !== RegExp) return [ false ]
return [ true, maybeRegex.toString() ]
}
export function equals(a, b){
if (arguments.length === 1) return _b => equals(a, _b)
const aType = type(a)
if (aType !== type(b)) return false
if (aType === 'Function'){
return a.name === undefined ? false : a.name === b.name
}
if ([ 'NaN', 'Undefined', 'Null' ].includes(aType)) return true
if (aType === 'Number'){
if (Object.is(-0, a) !== Object.is(-0, b)) return false
return a.toString() === b.toString()
}
if ([ 'String', 'Boolean' ].includes(aType)){
return a.toString() === b.toString()
}
if (aType === 'Array'){
const aClone = Array.from(a)
const bClone = Array.from(b)
if (aClone.toString() !== bClone.toString()){
return false
}
let loopArrayFlag = true
aClone.forEach((aCloneInstance, aCloneIndex) => {
if (loopArrayFlag){
if (
aCloneInstance !== bClone[ aCloneIndex ] &&
!equals(aCloneInstance, bClone[ aCloneIndex ])
){
loopArrayFlag = false
}
}
})
return loopArrayFlag
}
const aRegex = parseRegex(a)
const bRegex = parseRegex(b)
if (aRegex[ 0 ]){
return bRegex[ 0 ] ? aRegex[ 1 ] === bRegex[ 1 ] : false
} else if (bRegex[ 0 ]) return false
const aDate = parseDate(a)
const bDate = parseDate(b)
if (aDate[ 0 ]){
return bDate[ 0 ] ? aDate[ 1 ] === bDate[ 1 ] : false
} else if (bDate[ 0 ]) return false
const aError = parseError(a)
const bError = parseError(b)
if (aError[ 0 ]){
return bError[ 0 ] ?
aError[ 0 ] === bError[ 0 ] && aError[ 1 ] === bError[ 1 ] :
false
}
if (aType === 'Object'){
const aKeys = Object.keys(a)
if (aKeys.length !== Object.keys(b).length){
return false
}
let loopObjectFlag = true
aKeys.forEach(aKeyInstance => {
if (loopObjectFlag){
const aValue = a[ aKeyInstance ]
const bValue = b[ aKeyInstance ]
if (aValue !== bValue && !equals(aValue, bValue)){
loopObjectFlag = false
}
}
})
return loopObjectFlag
}
return false
}
import { equals } from './equals'
test('compare functions', () => {
function foo(){}
function bar(){}
const baz = () => {}
const expectTrue = equals(foo, foo)
const expectFalseFirst = equals(foo, bar)
const expectFalseSecond = equals(foo, baz)
expect(expectTrue).toBeTrue()
expect(expectFalseFirst).toBeFalse()
expect(expectFalseSecond).toBeFalse()
})
test('with array of objects', () => {
const list1 = [ { a : 1 }, [ { b : 2 } ] ]
const list2 = [ { a : 1 }, [ { b : 2 } ] ]
const list3 = [ { a : 1 }, [ { b : 3 } ] ]
expect(equals(list1, list2)).toBeTrue()
expect(equals(list1, list3)).toBeFalse()
})
test('with regex', () => {
expect(equals(/s/, /s/)).toEqual(true)
expect(equals(/s/, /d/)).toEqual(false)
expect(equals(/a/gi, /a/gi)).toEqual(true)
expect(equals(/a/gim, /a/gim)).toEqual(true)
expect(equals(/a/gi, /a/i)).toEqual(false)
})
test('not a number', () => {
expect(equals([ NaN ], [ NaN ])).toBeTrue()
})
test('new number', () => {
expect(equals(new Number(0), new Number(0))).toEqual(true)
expect(equals(new Number(0), new Number(1))).toEqual(false)
expect(equals(new Number(1), new Number(0))).toEqual(false)
})
test('new string', () => {
expect(equals(new String(''), new String(''))).toEqual(true)
expect(equals(new String(''), new String('x'))).toEqual(false)
expect(equals(new String('x'), new String(''))).toEqual(false)
expect(equals(new String('foo'), new String('foo'))).toEqual(true)
expect(equals(new String('foo'), new String('bar'))).toEqual(false)
expect(equals(new String('bar'), new String('foo'))).toEqual(false)
})
test('new Boolean', () => {
expect(equals(new Boolean(true), new Boolean(true))).toEqual(true)
expect(equals(new Boolean(false), new Boolean(false))).toEqual(true)
expect(equals(new Boolean(true), new Boolean(false))).toEqual(false)
expect(equals(new Boolean(false), new Boolean(true))).toEqual(false)
})
test('new Error', () => {
expect(equals(new Error('XXX'), {})).toEqual(false)
expect(equals(new Error('XXX'), new TypeError('XXX'))).toEqual(false)
expect(equals(new Error('XXX'), new Error('YYY'))).toEqual(false)
expect(equals(new Error('XXX'), new Error('XXX'))).toEqual(true)
expect(equals(new Error('XXX'), new TypeError('YYY'))).toEqual(false)
})
test('with dates', () => {
expect(equals(new Date(0), new Date(0))).toEqual(true)
expect(equals(new Date(1), new Date(1))).toEqual(true)
expect(equals(new Date(0), new Date(1))).toEqual(false)
expect(equals(new Date(1), new Date(0))).toEqual(false)
expect(equals(new Date(0), {})).toEqual(false)
expect(equals({}, new Date(0))).toEqual(false)
})
test('ramda spec', () => {
expect(equals({}, {})).toEqual(true)
expect(equals({
a : 1,
b : 2,
},
{
a : 1,
b : 2,
})).toEqual(true)
expect(equals({
a : 2,
b : 3,
},
{
b : 3,
a : 2,
})).toEqual(true)
expect(equals({
a : 2,
b : 3,
},
{
a : 3,
b : 3,
})).toEqual(false)
expect(equals({
a : 2,
b : 3,
c : 1,
},
{
a : 2,
b : 3,
})).toEqual(false)
})
test('works with boolean tuple', () => {
expect(equals([ true, false ], [ true, false ])).toBeTrue()
expect(equals([ true, false ], [ true, true ])).toBeFalse()
})
test('works with equal objects within array', () => {
const objFirst = {
a : {
b : 1,
c : 2,
d : [ 1 ],
},
}
const objSecond = {
a : {
b : 1,
c : 2,
d : [ 1 ],
},
}
const x = [ 1, 2, objFirst, null, '', [] ]
const y = [ 1, 2, objSecond, null, '', [] ]
expect(equals(x, y)).toBeTrue()
})
test('works with different objects within array', () => {
const objFirst = { a : { b : 1 } }
const objSecond = { a : { b : 2 } }
const x = [ 1, 2, objFirst, null, '', [] ]
const y = [ 1, 2, objSecond, null, '', [] ]
expect(equals(x, y)).toBeFalse()
})
test('works with undefined as second argument', () => {
expect(equals(1, undefined)).toBeFalse()
expect(equals(undefined, undefined)).toBeTrue()
})
test('various examples', () => {
expect(equals([ 1, 2, 3 ])([ 1, 2, 3 ])).toBeTrue()
expect(equals([ 1, 2, 3 ], [ 1, 2 ])).toBeFalse()
expect(equals(1, 1)).toBeTrue()
expect(equals(1, '1')).toBeFalse()
expect(equals({}, {})).toBeTrue()
expect(equals({
a : 1,
b : 2,
},
{
b : 2,
a : 1,
})).toBeTrue()
expect(equals({
a : 1,
b : 2,
},
{
a : 1,
b : 1,
})).toBeFalse()
expect(equals({
a : 1,
b : false,
},
{
a : 1,
b : 1,
})).toBeFalse()
expect(equals({
a : 1,
b : 2,
},
{
b : 2,
a : 1,
c : 3,
})).toBeFalse()
expect(equals({
x : {
a : 1,
b : 2,
},
},
{
x : {
b : 2,
a : 1,
c : 3,
},
})).toBeFalse()
expect(equals({
a : 1,
b : 2,
},
{
b : 3,
a : 1,
})).toBeFalse()
expect(equals({ a : { b : { c : 1 } } }, { a : { b : { c : 1 } } })).toBeTrue()
expect(equals({ a : { b : { c : 1 } } }, { a : { b : { c : 2 } } })).toBeFalse()
expect(equals({ a : {} }, { a : {} })).toBeTrue()
expect(equals('', '')).toBeTrue()
expect(equals('foo', 'foo')).toBeTrue()
expect(equals('foo', 'bar')).toBeFalse()
expect(equals(0, false)).toBeFalse()
expect(equals(/\s/g, null)).toBeFalse()
expect(equals(null, null)).toBeTrue()
expect(equals(false)(null)).toBeFalse()
})
test('with custom functions', () => {
function foo(){
return 1
}
foo.prototype.toString = () => ''
const result = equals(foo, foo)
expect(result).toBeTrue()
})
test('with classes', () => {
class Foo{}
const foo = new Foo()
const result = equals(foo, foo)
expect(result).toBeTrue()
})
test('with negative zero', () => {
expect(equals(-0, -0)).toBeTrue()
expect(equals(-0, 0)).toBeFalse()
expect(equals(0, 0)).toBeTrue()
expect(equals(-0, 1)).toBeFalse()
})
evolve<T, U>(rules: ((x: T) => U)[], list: T[]): U[]
It takes object or array of functions as set of rules. These rules are applied to the iterable input to produce the result.
:boom: Error handling of this method differs between Ramda and Rambda. Ramda for some wrong inputs returns result and for other - it returns one of the inputs. Rambda simply throws when inputs are not correct. Full details for this mismatch are listed in
source/_snapshots/evolve.spec.js.snapfile.
const rules = {
foo : add(1),
bar : add(-1),
}
const input = {
a : 1,
foo : 2,
bar : 3,
}
const result = evolve(rules, input)
const expected = {
a : 1,
foo : 3,
bar : 2,
})
// => `result` is equal to `expected`
Try this R.evolve example in Rambda REPL
import { _isArray } from './_internals/_isArray'
import { mapArray, mapObject } from './map'
import { type } from './type'
export function evolveArray(rules, list){
return mapArray(
(x, i) => {
if (type(rules[ i ]) === 'Function'){
return rules[ i ](x)
}
return x
},
list,
true
)
}
export function evolveObject(rules, iterable){
return mapObject((x, prop) => {
if (type(x) === 'Object'){
const typeRule = type(rules[ prop ])
if (typeRule === 'Function'){
return rules[ prop ](x)
}
if (typeRule === 'Object'){
return evolve(rules[ prop ], x)
}
return x
}
if (type(rules[ prop ]) === 'Function'){
return rules[ prop ](x)
}
return x
}, iterable)
}
export function evolve(rules, iterable){
if (arguments.length === 1){
return _iterable => evolve(rules, _iterable)
}
const rulesType = type(rules)
const iterableType = type(iterable)
if (iterableType !== rulesType){
throw new Error('iterableType !== rulesType')
}
if (![ 'Object', 'Array' ].includes(rulesType)){
throw new Error(`'iterable' and 'rules' are from wrong type ${ rulesType }`)
}
if (iterableType === 'Object'){
return evolveObject(rules, iterable)
}
return evolveArray(rules, iterable)
}
import { evolve as evolveRamda } from 'ramda'
import { add } from '../rambda'
import { compareCombinations, compareToRamda } from './_internals/testUtils'
import { evolve } from './evolve'
test('happy', () => {
const rules = {
foo : add(1),
nested : { bar : x => Object.keys(x).length },
}
const input = {
a : 1,
foo : 2,
nested : { bar : { z : 3 } },
}
const result = evolve(rules, input)
expect(result).toEqual({
a : 1,
foo : 3,
nested : { bar : 1 },
})
})
test('nested rule is wrong', () => {
const rules = {
foo : add(1),
nested : { bar : 10 },
}
const input = {
a : 1,
foo : 2,
nested : { bar : { z : 3 } },
}
const result = evolve(rules)(input)
expect(result).toEqual({
a : 1,
foo : 3,
nested : { bar : { z : 3 } },
})
})
test('is recursive', () => {
const rules = {
nested : {
second : add(-1),
third : add(1),
},
}
const object = {
first : 1,
nested : {
second : 2,
third : 3,
},
}
const expected = {
first : 1,
nested : {
second : 1,
third : 4,
},
}
const result = evolve(rules, object)
expect(result).toEqual(expected)
})
test('ignores primitive values', () => {
const rules = {
n : 2,
m : 'foo',
}
const object = {
n : 0,
m : 1,
}
const expected = {
n : 0,
m : 1,
}
const result = evolve(rules, object)
expect(result).toEqual(expected)
})
test('with array', () => {
const rules = [ add(1), add(-1) ]
const list = [ 100, 1400 ]
const expected = [ 101, 1399 ]
const result = evolve(rules, list)
expect(result).toEqual(expected)
})
const rulesObject = { a : add(1) }
const rulesList = [ add(1) ]
const possibleIterables = [ null, undefined, '', 42, [], [ 1 ], { a : 1 } ]
const possibleRules = [ ...possibleIterables, rulesList, rulesObject ]
describe('brute force', () => {
compareCombinations({
firstInput : possibleRules,
callback : errorsCounters => {
expect(errorsCounters).toMatchInlineSnapshot(`
Object {
"ERRORS_MESSAGE_MISMATCH": 0,
"ERRORS_TYPE_MISMATCH": 4,
"RESULTS_MISMATCH": 0,
"SHOULD_NOT_THROW": 51,
"SHOULD_THROW": 0,
}
`)
},
secondInput : possibleIterables,
fn : evolve,
fnRamda : evolveRamda,
})
})
excludes(valueToFind: string, input: string[] | string): boolean
Opposite of R.includes
R.equals is used to determine equality.
const result = [
R.excludes('ar', 'foo'),
R.excludes({a: 2}, [{a: 1}])
]
// => [true, true ]
Try this R.excludes example in Rambda REPL
import { includes } from './includes'
export function excludes(valueToFind, input){
if (arguments.length === 1) return _input => excludes(valueToFind, _input)
return includes(valueToFind, input) === false
}
import { excludes } from './excludes'
test('excludes with string', () => {
const str = 'more is less'
expect(excludes('less')(str)).toBeFalse()
expect(excludes('never', str)).toBeTrue()
})
test('excludes with array', () => {
const arr = [ 1, 2, 3 ]
expect(excludes(2)(arr)).toBeFalse()
expect(excludes(4, arr)).toBeTrue()
})
F(): boolean
F() // => false
Try this R.F example in Rambda REPL
export function F(){
return false
}
filter<T>(predicate: Predicate<T>): (input: T[]) => T[]
It filters list or object input using a predicate function.
const list = [3, 4, 3, 2]
const listPredicate = x => x > 2
const object = {abc: 'fo', xyz: 'bar', baz: 'foo'}
const objectPredicate = (x, prop) => x.length + prop.length > 5
const result = [
R.filter(listPredicate, list),
R.filter(objectPredicate, object)
]
// => [ [3, 4], { xyz: 'bar', baz: 'foo'} ]
Try this R.filter example in Rambda REPL
import { _isArray } from './_internals/_isArray'
export function filterObject(predicate, obj){
const willReturn = {}
for (const prop in obj){
if (predicate(obj[ prop ], prop, obj)){
willReturn[ prop ] = obj[ prop ]
}
}
return willReturn
}
export function filterArray(
predicate, list, indexed = false
){
let index = 0
const len = list.length
const willReturn = []
while (index < len){
const predicateResult = indexed ?
predicate(list[ index ], index) :
predicate(list[ index ])
if (predicateResult){
willReturn.push(list[ index ])
}
index++
}
return willReturn
}
export function filter(predicate, iterable){
if (arguments.length === 1){
return _iterable => filter(predicate, _iterable)
}
if (!iterable) return []
if (_isArray(iterable)) return filterArray(predicate, iterable)
return filterObject(predicate, iterable)
}
import Ramda from 'ramda'
import { F } from './F'
import { filter } from './filter'
import { T } from './T'
const sampleObject = {
a : 1,
b : 2,
c : 3,
d : 4,
}
test('happy', () => {
const isEven = n => n % 2 === 0
expect(filter(isEven, [ 1, 2, 3, 4 ])).toEqual([ 2, 4 ])
expect(filter(isEven, {
a : 1,
b : 2,
d : 3,
})).toEqual({ b : 2 })
})
test('bad inputs difference between Ramda and Rambda', () => {
expect(filter(T)(undefined)).toEqual([])
expect(filter(F, null)).toEqual([])
expect(() => Ramda.filter(T, null)).toThrowWithMessage(TypeError,
'Cannot read property \'filter\' of null')
expect(() => Ramda.filter(T, undefined)).toThrowWithMessage(TypeError,
'Cannot read property \'filter\' of undefined')
})
test.only('predicate when input is object', () => {
const obj = {
a : 1,
b : 2,
}
const predicate = (
val, prop, inputObject
) => {
expect(inputObject).toEqual(obj)
expect(typeof prop).toEqual('string')
return val < 2
}
expect(filter(predicate, obj)).toEqual({ a : 1 })
})
test('with object', () => {
const isEven = n => n % 2 === 0
const result = filter(isEven, sampleObject)
const expectedResult = {
b : 2,
d : 4,
}
expect(result).toEqual(expectedResult)
})
filterArray<T>(predicate: Predicate<T>): (input: T[]) => T[]
const result = R.filterArray(
x => x > 1,
[1, 2, 3]
)
// => [1, 3]
Try this R.filterArray example in Rambda REPL
filterAsync<T>(fn: AsyncPredicate<T>, list: T[]): Promise<T[]>
Asynchronous version of R.filter
const predicate = async x => {
await R.delay(100)
return x % 2 === 1
}
const result = await R.filterAsync(predicate, [ 1, 2, 3 ])
// => [ 1, 3 ]
Try this R.filterAsync example in Rambda REPL
import { _isArray } from './_internals/_isArray'
import { filter } from './filter'
import { mapAsync } from './mapAsync'
export function filterAsyncFn(predicate, listOrObject){
return new Promise((resolve, reject) => {
mapAsync(predicate, listOrObject)
.then(predicateResult => {
if (_isArray(predicateResult)){
const filtered = listOrObject.filter((_, i) => predicateResult[ i ])
return resolve(filtered)
}
const filtered = filter((_, prop) => predicateResult[ prop ],
listOrObject)
return resolve(filtered)
})
.catch(reject)
})
}
export function filterAsync(predicate, listOrObject){
if (arguments.length === 1){
return async _listOrObject => filterAsyncFn(predicate, _listOrObject)
}
return new Promise((resolve, reject) => {
filterAsyncFn(predicate, listOrObject).then(resolve)
.catch(reject)
})
}
import { delay } from './delay'
import { filterAsync } from './filterAsync'
test('happy', async () => {
const predicate = async (x, i) => {
expect(i).toBeNumber()
await delay(100)
return x % 2 === 1
}
const result = await filterAsync(predicate)([ 1, 2, 3 ])
expect(result).toEqual([ 1, 3 ])
})
test('with object', async () => {
const predicate = async (x, prop) => {
expect(prop).toBeString()
await delay(100)
return x % 2 === 1
}
const result = await filterAsync(predicate, {
a : 1,
b : 2,
c : 3,
d : 4,
e : 5,
})
expect(result).toEqual({
a : 1,
c : 3,
e : 5,
})
})
Same as R.filter, but it passes index/property as second argument to the predicate, when looping over arrays/objects.
filterObject<T>(predicate: ObjectPredicate<T>): (x: Dictionary<T>) => Dictionary<T>
const obj = {a: 1, b:2}
const result = R.filterObject(
x => x > 1,
obj
)
// => {b: 2}
Try this R.filterObject example in Rambda REPL
find<T>(predicate: (x: T) => boolean, list: T[]): T | undefined
It returns the first element of list that satisfy the predicate.
If there is no such element, it returns undefined.
const predicate = x => R.type(x.foo) === 'Number'
const list = [{foo: 'bar'}, {foo: 1}]
const result = R.find(predicate, list)
// => {foo: 1}
Try this R.find example in Rambda REPL
export function find(predicate, list){
if (arguments.length === 1) return _list => find(predicate, _list)
let index = 0
const len = list.length
while (index < len){
const x = list[ index ]
if (predicate(x)){
return x
}
index++
}
}
import { find } from './find'
import { propEq } from './propEq'
const list = [ { a : 1 }, { a : 2 }, { a : 3 } ]
test('happy', () => {
const fn = propEq('a', 2)
expect(find(fn, list)).toEqual({ a : 2 })
})
test('with curry', () => {
const fn = propEq('a', 4)
expect(find(fn)(list)).toBeUndefined()
})
test('with empty list', () => {
expect(find(() => true, [])).toBeUndefined()
})
findIndex<T>(predicate: (x: T) => boolean, list: T[]): number
It returns the index of the first element of list satisfying the predicate function.
If there is no such element, then -1 is returned.
const predicate = x => R.type(x.foo) === 'Number'
const list = [{foo: 'bar'}, {foo: 1}]
const result = R.findIndex(predicate, list)
// => 1
Try this R.findIndex example in Rambda REPL
export function findIndex(predicate, list){
if (arguments.length === 1) return _list => findIndex(predicate, _list)
const len = list.length
let index = -1
while (++index < len){
if (predicate(list[ index ])){
return index
}
}
return -1
}
import { findIndex } from './findIndex'
import { propEq } from './propEq'
const list = [ { a : 1 }, { a : 2 }, { a : 3 } ]
test('happy', () => {
expect(findIndex(propEq('a', 2), list)).toEqual(1)
expect(findIndex(propEq('a', 1))(list)).toEqual(0)
expect(findIndex(propEq('a', 4))(list)).toEqual(-1)
})
findLast<T>(fn: (x: T) => boolean, list: T[]): T | undefined
It returns the last element of list satisfying the predicate function.
If there is no such element, then undefined is returned.
const predicate = x => R.type(x.foo) === 'Number'
const list = [{foo: 0}, {foo: 1}]
const result = R.findLast(predicate, list)
// => {foo: 1}
Try this R.findLast example in Rambda REPL
export function findLast(predicate, list){
if (arguments.length === 1) return _list => findLast(predicate, _list)
let index = list.length
while (--index >= 0){
if (predicate(list[ index ])){
return list[ index ]
}
}
return undefined
}
import { findLast } from './findLast'
test('happy', () => {
const result = findLast(x => x > 1,
[ 1, 1, 1, 2, 3, 4, 1 ])
expect(result).toEqual(4)
expect(findLast(x => x === 0, [ 0, 1, 1, 2, 3, 4, 1 ])).toEqual(0)
})
test('with curry', () => {
expect(findLast(x => x > 1)([ 1, 1, 1, 2, 3, 4, 1 ])).toEqual(4)
})
const obj1 = { x : 100 }
const obj2 = { x : 200 }
const a = [ 11, 10, 9, 'cow', obj1, 8, 7, 100, 200, 300, obj2, 4, 3, 2, 1, 0 ]
const even = function (x){
return x % 2 === 0
}
const gt100 = function (x){
return x > 100
}
const isStr = function (x){
return typeof x === 'string'
}
const xGt100 = function (o){
return o && o.x > 100
}
test('ramda 1', () => {
expect(findLast(even, a)).toEqual(0)
expect(findLast(gt100, a)).toEqual(300)
expect(findLast(isStr, a)).toEqual('cow')
expect(findLast(xGt100, a)).toEqual(obj2)
})
test('ramda 2', () => {
expect(findLast(even, [ 'zing' ])).toEqual(undefined)
})
test('ramda 3', () => {
expect(findLast(even, [ 2, 3, 5 ])).toEqual(2)
})
test('ramda 4', () => {
expect(findLast(even, [])).toEqual(undefined)
})
findLastIndex<T>(predicate: (x: T) => boolean, list: T[]): number
It returns the index of the last element of list satisfying the predicate function.
If there is no such element, then -1 is returned.
const predicate = x => R.type(x.foo) === 'Number'
const list = [{foo: 0}, {foo: 1}]
const result = R.findLastIndex(predicate, list)
// => 1
Try this R.findLastIndex example in Rambda REPL
export function findLastIndex(fn, list){
if (arguments.length === 1) return _list => findLastIndex(fn, _list)
let index = list.length
while (--index >= 0){
if (fn(list[ index ])){
return index
}
}
return -1
}
import { findLastIndex } from './findLastIndex'
test('happy', () => {
const result = findLastIndex(x => x > 1,
[ 1, 1, 1, 2, 3, 4, 1 ])
expect(result).toEqual(5)
expect(findLastIndex(x => x === 0, [ 0, 1, 1, 2, 3, 4, 1 ])).toEqual(0)
})
test('with curry', () => {
expect(findLastIndex(x => x > 1)([ 1, 1, 1, 2, 3, 4, 1 ])).toEqual(5)
})
const obj1 = { x : 100 }
const obj2 = { x : 200 }
const a = [ 11, 10, 9, 'cow', obj1, 8, 7, 100, 200, 300, obj2, 4, 3, 2, 1, 0 ]
const even = function (x){
return x % 2 === 0
}
const gt100 = function (x){
return x > 100
}
const isStr = function (x){
return typeof x === 'string'
}
const xGt100 = function (o){
return o && o.x > 100
}
test('ramda 1', () => {
expect(findLastIndex(even, a)).toEqual(15)
expect(findLastIndex(gt100, a)).toEqual(9)
expect(findLastIndex(isStr, a)).toEqual(3)
expect(findLastIndex(xGt100, a)).toEqual(10)
})
test('ramda 2', () => {
expect(findLastIndex(even, [ 'zing' ])).toEqual(-1)
})
test('ramda 3', () => {
expect(findLastIndex(even, [ 2, 3, 5 ])).toEqual(0)
})
test('ramda 4', () => {
expect(findLastIndex(even, [])).toEqual(-1)
})
flatten<T>(list: any[]): T[]
It deeply flattens an array.
const result = R.flatten([
1,
2,
[3, 30, [300]],
[4]
])
// => [ 1, 2, 3, 30, 300, 4 ]
Try this R.flatten example in Rambda REPL
import { _isArray } from './_internals/_isArray'
export function flatten(list, input){
const willReturn = input === undefined ? [] : input
for (let i = 0; i < list.length; i++){
if (_isArray(list[ i ])){
flatten(list[ i ], willReturn)
} else {
willReturn.push(list[ i ])
}
}
return willReturn
}
import { flatten } from './flatten'
test('happy', () => {
expect(flatten([ 1, 2, 3, [ [ [ [ [ 4 ] ] ] ] ] ])).toEqual([ 1, 2, 3, 4 ])
expect(flatten([ 1, [ 2, [ [ 3 ] ] ], [ 4 ] ])).toEqual([ 1, 2, 3, 4 ])
expect(flatten([ 1, [ 2, [ [ [ 3 ] ] ] ], [ 4 ] ])).toEqual([ 1, 2, 3, 4 ])
expect(flatten([ 1, 2, [ 3, 4 ], 5, [ 6, [ 7, 8, [ 9, [ 10, 11 ], 12 ] ] ] ])).toEqual([ 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 ])
})
test('readme example', () => {
const result = flatten([ 1, 2, [ 3, 30, [ 300 ] ], [ 4 ] ])
expect(result).toEqual([ 1, 2, 3, 30, 300, 4 ])
})
It returns function which calls fn with exchanged first and second argument.
:boom: Rambda's flip will throw if the arity of the input function is greater or equal to 5.
const subtractFlip = R.flip(R.subtract)
const result = [
subtractFlip(1,7),
R.subtract(1, 6)
]
// => [6, -6]
Try this R.flip example in Rambda REPL
forEach<T>(fn: Iterator<T, void>, list: T[]): T[]
It applies iterable function over all members of list and returns list.
:boom: It works with objects, unlike
Ramda.
const sideEffect = {}
const result = R.forEach(
x => sideEffect[`foo${x}`] = x
)([1, 2])
sideEffect // => {foo1: 1, foo2: 2}
result // => [1, 2]
Try this R.forEach example in Rambda REPL
import { _isArray } from './_internals/_isArray'
import { _keys } from './_internals/_keys'
export function forEach(fn, list){
if (arguments.length === 1) return _list => forEach(fn, _list)
if (list === undefined){
return
}
if (_isArray(list)){
let index = 0
const len = list.length
while (index < len){
fn(list[ index ])
index++
}
} else {
let index = 0
const keys = _keys(list)
const len = keys.length
while (index < len){
const key = keys[ index ]
fn(
list[ key ], key, list
)
index++
}
}
return list
}
import { forEach } from './forEach'
import { type } from './type'
test('happy', () => {
const sideEffect = {}
forEach(x => sideEffect[ `foo${ x }` ] = x + 10)([ 1, 2 ])
expect(sideEffect).toEqual({
foo1 : 11,
foo2 : 12,
})
})
test('iterate over object', () => {
const obj = {
a : 1,
b : [ 1, 2 ],
c : { d : 7 },
f : 'foo',
}
const result = {}
const returned = forEach((
val, prop, inputObj
) => {
expect(type(inputObj)).toBe('Object')
result[ prop ] = `${ prop }-${ type(val) }`
})(obj)
const expected = {
a : 'a-Number',
b : 'b-Array',
c : 'c-Object',
f : 'f-String',
}
expect(result).toEqual(expected)
expect(returned).toEqual(obj)
})
test('with empty list', () => {
const list = []
const result = forEach(x => x * x)(list)
expect(result).toEqual(list)
})
test('with wrong input', () => {
const list = undefined
const result = forEach(x => x * x)(list)
expect(result).toBeUndefined()
})
test('returns the input', () => {
const list = [ 1, 2, 3 ]
const result = forEach(x => x * x)(list)
expect(result).toEqual(list)
})
forEachIndexed<T>(fn: IndexedIterator<T, void>, list: T[]): T[]
import { mapIndexed } from './mapIndexed'
export function forEachIndexed(fn, iterable){
if (arguments.length === 1){
return _iterable => forEachIndexed(fn, _iterable)
}
mapIndexed(fn, iterable)
return iterable
}
import { forEachIndexed } from './forEachIndexed'
const list = [ 1, 2, 3 ]
const iterator = (x, i) => {
expect(x).toBeNumber()
expect(i).toBeNumber()
}
test('happy', () => {
const result = forEachIndexed(iterator, list)
expect(result).toEqual(list)
})
test('curried', () => {
const result = forEachIndexed(iterator)(list)
expect(result).toEqual(list)
})
It transforms a listOfPairs to an object.
const listOfPairs = [ [ 'a', 1 ], [ 'b', 2 ], [ 'c', [ 3, 4 ] ] ]
const expected = {
a : 1,
b : 2,
c : [ 3, 4 ],
}
const result = R.fromPairs(listOfPairs)
// => `result` is equal to `expected`
Try this R.fromPairs example in Rambda REPL
getter<T>(keyOrKeys: string | string[] | undefined): T
The set of methods R.setter, R.getter and R.reset allow different parts of your logic to access comminicate indirectly via shared cache object.
Usually these methods show that you might need to refactor to classes. Still, they can be helpful meanwhile.
R.getter: It provides access to the cache object. If undefined is used as a key, this method will return the whole cache object. If string is passed, then it will return cache value for this key. If array of string is passed, then it assume that this is array of keys and it will return the corresponding cache values for these keys.
R.setter: It allows cache object's keys to be changed. You can either set individual key-value pairs with R.setter(key, value) or you pass directly object, which will be merged with the cache object.
R.reset: It resets the cache object.
R.setter('foo','bar')
R.setter('a', 1)
R.getter(['foo','a']) // => {foo: 'bar', a: 1}
R.setter('a', 2)
R.getter('a') // => 2
R.reset()
R.getter('a') // => undefined
Try this R.getter example in Rambda REPL
import { merge } from './merge'
import { pick } from './pick'
import { type } from './type'
let holder = {}
/**
* Pass string to get value
* Pass array to get object of values
* Pass undefined to get all data
*/
export function getter(key){
const typeKey = type(key)
if (typeKey === 'String') return holder[ key ]
if (typeKey === 'Array') return pick(key, holder)
return holder
}
export function setter(maybeKey, maybeValue){
const typeKey = type(maybeKey)
const typeValue = type(maybeValue)
if (typeKey === 'String'){
if (typeValue === 'Function'){
return holder[ maybeKey ] = maybeValue(holder[ maybeKey ])
}
return holder[ maybeKey ] = maybeValue
}
if (typeKey !== 'Object') return
holder = merge(holder, maybeKey)
}
export function reset(){
holder = {}
}
import { add } from './add'
import { getter, reset, setter } from './getter'
afterEach(() => {
reset()
})
test('happy', () => {
const key = 'foo'
setter(key, 1)
expect(getter(key)).toBe(1)
})
test('docs example', () => {
setter('foo', 'bar')
setter('a', 1)
expect(getter([ 'foo', 'a' ])).toEqual({
foo : 'bar',
a : 1,
})
setter('a', 2)
expect(getter('a')).toBe(2)
reset()
expect(getter('a')).toBeUndefined()
})
test('when array is key in getter', () => {
setter({
a : 1,
b : 2,
c : 3,
})
expect(getter([ 'a', 'b' ])).toEqual({
a : 1,
b : 2,
})
})
test('getter with undefined as key returns all', () => {
const data = {
a : 1,
b : 2,
c : 3,
}
setter(data)
expect(getter()).toEqual(data)
})
test('function as setter value', () => {
const data = {
a : 1,
b : 2,
c : 3,
}
setter(data)
setter('a', add(10))
expect(getter()).toEqual({
a : 11,
b : 2,
c : 3,
})
})
test('setter fallbacks to undefined', () => {
expect(setter()).toBeUndefined
})
glue(input: string, glueString?: string): string
It transforms multiline string to single line by gluing together the separate lines with the glueString and removing the empty spaces. By default glueString is equal to single space, so if that is what you need, then you can just pass a single argument.
const result = R.glue(`
foo
bar
baz
`)
// => 'foo bar baz'
Try this R.glue example in Rambda REPL
export function glue(input, glueChar){
return input
.split('\n')
.filter(x => x.trim().length > 0)
.map(x => x.trim())
.join(glueChar === undefined ? ' ' : glueChar)
}
import { glue } from './glue'
test('empty string as a glue', () => {
const result = glue(`
foo
bar
baz
`,
'')
const expectedResult = 'foobarbaz'
expect(result).toBe(expectedResult)
})
test('case 0', () => {
const zero = 'node node_modules/jest'
const first = '--runInBand'
const last = '-- src/a.spec.js'
const flag = false
const result = glue(`
${ zero }
${ first }
${ flag ? '--env=node' : '' }
${ last }
`)
const expectedResult = `${ zero } ${ first } ${ last }`
expect(result).toBe(expectedResult)
})
test('case 1', () => {
const zero = 'node node_modules/jest'
const first = '--runInBand'
const last = '-- src/a.spec.js'
const flag = true
const result = glue(`
${ zero }
${ first }
${ flag ? '--env=node' : '' }
${ last }
`)
const expectedResult = `${ zero } ${ first } --env=node ${ last }`
expect(result).toBe(expectedResult)
})
test('case 2', () => {
const first = '--runInBand'
const result = glue(`
zero
${ first }
last
`)
const expectedResult = `zero ${ first } last`
expect(result).toBe(expectedResult)
})
test('case 3', () => {
const result = glue(`
foo
bar
baz
`)
const expectedResult = 'foo bar baz'
expect(result).toBe(expectedResult)
})
test('with glue', () => {
const result = glue(`
foo
bar
baz
`,
'==')
const expectedResult = 'foo==bar==baz'
expect(result).toBe(expectedResult)
})
It splits list according to a provided groupFn function and returns an object.
const list = [ 'a', 'b', 'aa', 'bb' ]
const groupFn = x => x.length
const result = R.groupBy(groupFn, list)
// => { '1': ['a', 'b'], '2': ['aa', 'bb'] }
Try this R.groupBy example in Rambda REPL
groupWith<T>(compareFn: (x: T, y: T) => boolean): (input: T[]) => (T[])[]
It returns separated version of list or string input, where separation is done with equality compareFn function.
const compareFn = (x, y) => x === y
const list = [1, 2, 2, 1, 1, 2]
const result = R.groupWith(isConsecutive, list)
// => [[1], [2,2], [1,1], [2]]
Try this R.groupWith example in Rambda REPL
import { _isArray } from './_internals/_isArray'
export function groupWith(compareFn, list){
if (!_isArray(list)) throw new TypeError('list.reduce is not a function')
const clone = list.slice()
if (list.length === 1) return [ clone ]
const toReturn = []
let holder = []
clone.reduce((
prev, current, i
) => {
if (i === 0) return current
const okCompare = compareFn(prev, current)
const holderIsEmpty = holder.length === 0
const lastCall = i === list.length - 1
if (okCompare){
if (holderIsEmpty) holder.push(prev)
holder.push(current)
if (lastCall) toReturn.push(holder)
return current
}
if (holderIsEmpty){
toReturn.push([ prev ])
if (lastCall) toReturn.push([ current ])
return current
}
toReturn.push(holder)
if (lastCall) toReturn.push([ current ])
holder = []
return current
}, undefined)
return toReturn
}
import { equals } from './equals'
import { groupWith } from './groupWith'
test('issue is fixed', () => {
const result = groupWith(equals, [ 1, 2, 2, 3 ])
const expected = [ [ 1 ], [ 2, 2 ], [ 3 ] ]
expect(result).toEqual(expected)
})
test('long list', () => {
const result = groupWith(equals, [
0,
1,
1,
2,
3,
5,
8,
13,
21,
21,
21,
1,
2,
])
const expected = [
[ 0 ],
[ 1, 1 ],
[ 2 ],
[ 3 ],
[ 5 ],
[ 8 ],
[ 13 ],
[ 21, 21, 21 ],
[ 1 ],
[ 2 ],
]
expect(result).toEqual(expected)
})
test('readme example', () => {
const list = [ 4, 3, 6, 2, 2, 1 ]
const result = groupWith((a, b) => a - b === 1, list)
const expected = [ [ 4, 3 ], [ 6 ], [ 2 ], [ 2, 1 ] ]
expect(result).toEqual(expected)
})
test('throw with string as input', () => {
expect(() => groupWith(equals, 'Mississippi')).toThrowWithMessage(TypeError,
'list.reduce is not a function')
})
const isConsecutive = function (a, b){
return a + 1 === b
}
test('fix coverage', () => {
expect(groupWith(isConsecutive, [ 1, 2, 3, 0 ])).toEqual([ [ 1, 2, 3 ], [ 0 ] ])
})
test('from ramda 0', () => {
expect(groupWith(equals, [])).toEqual([])
expect(groupWith(isConsecutive, [])).toEqual([])
})
test('from ramda 1', () => {
expect(groupWith(isConsecutive, [ 4, 3, 2, 1 ])).toEqual([
[ 4 ],
[ 3 ],
[ 2 ],
[ 1 ],
])
})
test('from ramda 2', () => {
expect(groupWith(isConsecutive, [ 1, 2, 3, 4 ])).toEqual([ [ 1, 2, 3, 4 ] ])
})
test('from ramda 3', () => {
expect(groupWith(isConsecutive, [ 1, 2, 2, 3 ])).toEqual([
[ 1, 2 ],
[ 2, 3 ],
])
expect(groupWith(isConsecutive, [ 1, 2, 9, 3, 4 ])).toEqual([
[ 1, 2 ],
[ 9 ],
[ 3, 4 ],
])
})
test('list with single item', () => {
const result = groupWith(equals, [ 0 ])
const expected = [ [ 0 ] ]
expect(result).toEqual(expected)
})
has<T>(prop: string, obj: T): boolean
It returns true if obj has property prop.
const obj = {a: 1}
const result = [
R.has('a', obj),
R.has('b', obj)
]
// => [true, false]
Try this R.has example in Rambda REPL
export function has(prop, obj) {
if (arguments.length === 1) return _obj => has(prop, _obj)
if (!obj) return false
return obj.hasOwnProperty(prop)
}
import { has } from './has'
test('happy', () => {
expect(has('a')({ a : 1 })).toBeTrue()
expect(has('b', { a : 1 })).toBeFalse()
})
test('with non-object', () => {
expect(has('a', undefined)).toEqual(false)
expect(has('a', null)).toEqual(false)
expect(has('a', true)).toEqual(false)
expect(has('a', '')).toEqual(false)
expect(has('a', /a/)).toEqual(false)
})
hasPath<T>(
path: string | string[],
input: object
): boolean
It will return true, if input object has truthy path(calculated with R.path).
const path = 'a.b'
const pathAsArray = ['a', 'b']
const obj = {a: {b: []}}
const result = [
R.hasPath(path, obj),
R.hasPath(pathAsArray, obj),
R.hasPath('a.c', obj),
]
// => [true, true, false]
Try this R.hasPath example in Rambda REPL
import { path } from './path'
export function hasPath(maybePath, obj){
if (arguments.length === 1){
return objHolder => hasPath(maybePath, objHolder)
}
return path(maybePath, obj) !== undefined
}
import { hasPath } from './hasPath'
test('when true', () => {
const path = 'a.b'
const obj = { a : { b : [] } }
const result = hasPath(path)(obj)
const expectedResult = true
expect(result).toEqual(expectedResult)
})
test('when false', () => {
const path = 'a.b'
const obj = {}
const result = hasPath(path, obj)
const expectedResult = false
expect(result).toEqual(expectedResult)
})
head<T>(input: T[]): T | undefined
It returns the first element of list or string input.
const result = [
R.head([1, 2, 3]),
R.head('foo')
]
// => [1, 'f']
Try this R.head example in Rambda REPL
export function head(listOrString){
if (typeof listOrString === 'string') return listOrString[ 0 ] || ''
return listOrString[ 0 ]
}
import { head } from './head'
test('head', () => {
expect(head([ 'fi', 'fo', 'fum' ])).toEqual('fi')
expect(head([])).toEqual(undefined)
expect(head('foo')).toEqual('f')
expect(head('')).toEqual('')
})
It returns true if its arguments a and b are identical.
Otherwise, it returns false.
:boom: Values are identical if they reference the same memory.
NaNis identical toNaN;0and-0are not identical.
const obj = {a: 1};
R.identical(obj, obj); // => true
R.identical(1, 1); // => true
R.identical(1, '1'); // => false
R.identical([], []); // => false
R.identical(0, -0); // => false
R.identical(NaN, NaN); // => true
Try this R.identical example in Rambda REPL
identity<T>(input: T): T
It just passes back the supplied input argument.
:boom: Logic
R.identity(7) // => 7
Try this R.identity example in Rambda REPL
export function identity(input){
return input
}
import { identity } from './identity'
test('happy', () => {
expect(identity(7)).toEqual(7)
expect(identity(true)).toEqual(true)
expect(identity({ a : 1 })).toEqual({ a : 1 })
})
ifElse<T, U>(
condition: (x: T) => boolean,
onTrue: (x: T) => U,
onFalse: (x: T) => U,
): (x: T) => U
It expects condition, onTrue and onFalse functions as inputs and it returns a new function with example name of fn.
When fn`` is called with inputargument, it will return eitheronTrue(input)oronFalse(input)depending oncondition(input)` evaluation.
const fn = R.ifElse(
x => x>10,
x => x*2,
x => x*10
)
const result = [ fn(8), fn(18) ]
// => [80, 36]
Try this R.ifElse example in Rambda REPL
import { curry } from './curry'
function ifElseFn(
condition, onTrue, onFalse
){
return (...input) => {
const conditionResult =
typeof condition === 'boolean' ? condition : condition(...input)
if (conditionResult === true){
return onTrue(...input)
}
return onFalse(...input)
}
}
export const ifElse = curry(ifElseFn)
import { always } from './always'
import { has } from './has'
import { identity } from './identity'
import { ifElse } from './ifElse'
import { prop } from './prop'
const condition = has('foo')
const v = function (a){
return typeof a === 'number'
}
const t = function (a){
return a + 1
}
const ifFn = x => prop('foo', x).length
const elseFn = () => false
test('happy', () => {
const fn = ifElse(condition, ifFn)(elseFn)
expect(fn({ foo : 'bar' })).toEqual(3)
expect(fn({ fo : 'bar' })).toEqual(false)
})
test('ramda spec', () => {
const ifIsNumber = ifElse(v)
expect(ifIsNumber(t, identity)(15)).toEqual(16)
expect(ifIsNumber(t, identity)('hello')).toEqual('hello')
})
test('pass all arguments', () => {
const identity = function (a){
return a
}
const v = function (){
return true
}
const onTrue = function (a, b){
expect(a).toEqual(123)
expect(b).toEqual('abc')
}
ifElse(
v, onTrue, identity
)(123, 'abc')
})
test('accept constant as condition', () => {
const fn = ifElse(true)(always(true))(always(false))
expect(fn()).toEqual(true)
})
test('accept constant as condition - case 2', () => {
const fn = ifElse(
false, always(true), always(false)
)
expect(fn()).toEqual(false)
})
test('curry 1', () => {
const fn = ifElse(condition, ifFn)(elseFn)
expect(fn({ foo : 'bar' })).toEqual(3)
expect(fn({ fo : 'bar' })).toEqual(false)
})
test('curry 2', () => {
const fn = ifElse(condition)(ifFn)(elseFn)
expect(fn({ foo : 'bar' })).toEqual(3)
expect(fn({ fo : 'bar' })).toEqual(false)
})
test('simple arity of 1', () => {
const condition = x => x > 5
const onTrue = x => x + 1
const onFalse = x => x + 10
const result = ifElse(
condition, onTrue, onFalse
)(1)
expect(result).toBe(11)
})
test('simple arity of 2', () => {
const condition = (x, y) => x + y > 5
const onTrue = (x, y) => x + y + 1
const onFalse = (x, y) => x + y + 10
const result = ifElse(
condition, onTrue, onFalse
)(1, 10)
expect(result).toBe(12)
})
ifElseAsync<T, U>(
condition: (x: T) => Promise<boolean>,
onTrue: (x: T) => U,
onFalse: (x: T) => U,
): (x: T) => Promise<U>
Asynchronous version of R.ifElse. Any of condition, ifFn and elseFn can be either asynchronous or synchronous function.
const condition = async x => {
await R.delay(100)
return x > 1
}
const ifFn = async x => {
await R.delay(100)
return x + 1
}
const elseFn = async x => {
await R.delay(100)
return x - 1
}
const result = await R.ifElseAsync(
condition,
ifFn,
elseFn
)(1)
// => 0
Try this R.ifElseAsync example in Rambda REPL
function createThenable(fn){
return async function (...input){
return fn(...input)
}
}
export function ifElseAsync(
condition, ifFn, elseFn
){
return (...inputs) =>
new Promise((resolve, reject) => {
const conditionPromise = createThenable(condition)
const ifFnPromise = createThenable(ifFn)
const elseFnPromise = createThenable(elseFn)
conditionPromise(...inputs)
.then(conditionResult => {
const promised =
conditionResult === true ? ifFnPromise : elseFnPromise
promised(...inputs)
.then(resolve)
.catch(reject)
})
.catch(reject)
})
}
import { delay } from './delay'
import { ifElseAsync } from './ifElseAsync'
test('arity of 1 - condition is async', async () => {
const condition = async x => {
await delay(100)
return x > 4
}
const whenTrue = x => x + 1
const whenFalse = x => x + 10
const fn = ifElseAsync(
condition, whenTrue, whenFalse
)
const result = await Promise.all([ fn(5), fn(1) ])
expect(result).toEqual([ 6, 11 ])
})
test('arity of 1 - condition is sync', async () => {
const condition = x => x > 4
const whenTrue = async x => {
await delay(100)
return x + 1
}
const whenFalse = async x => {
await delay(100)
return x + 10
}
const fn = ifElseAsync(
condition, whenTrue, whenFalse
)
const result = await Promise.all([ fn(5), fn(1) ])
expect(result).toEqual([ 6, 11 ])
})
test('arity of 1 - all inputs are async', async () => {
const condition = async x => {
await delay(100)
return x > 4
}
const whenTrue = async x => {
await delay(100)
return x + 1
}
const whenFalse = async x => {
await delay(100)
return x + 10
}
const fn = ifElseAsync(
condition, whenTrue, whenFalse
)
const result = await Promise.all([ fn(5), fn(1) ])
expect(result).toEqual([ 6, 11 ])
})
test('arity of 2 - condition is async', async () => {
const condition = async (x, y) => {
await delay(100)
return x + y > 4
}
const whenTrue = (x, y) => x + y + 1
const whenFalse = (x, y) => x + y + 10
const fn = ifElseAsync(
condition, whenTrue, whenFalse
)
const result = await Promise.all([ fn(14, 20), fn(1, 3) ])
expect(result).toEqual([ 35, 14 ])
})
test('arity of 2 - condition is sync', async () => {
const condition = (x, y) => x + y > 4
const whenTrue = async (x, y) => {
await delay(100)
return x + y + 1
}
const whenFalse = async (x, y) => {
await delay(100)
return x + y + 10
}
const fn = ifElseAsync(
condition, whenTrue, whenFalse
)
const result = await Promise.all([ fn(14, 20), fn(1, 3) ])
expect(result).toEqual([ 35, 14 ])
})
test('arity of 2 - all inputs are async', async () => {
const condition = async (x, y) => {
await delay(100)
return x + y > 4
}
const whenTrue = async (x, y) => {
await delay(100)
return x + y + 1
}
const whenFalse = async (x, y) => {
await delay(100)
return x + y + 10
}
const fn = ifElseAsync(
condition, whenTrue, whenFalse
)
const result = await Promise.all([ fn(14, 20), fn(1, 3) ])
expect(result).toEqual([ 35, 14 ])
})
It increments a number.
R.inc(1) // => 2
Try this R.inc example in Rambda REPL
includes(valueToFind: string, input: string[] | string): boolean
If input is string, then this method work as native String.includes.
If input is array, then R.equals is used to define if valueToFind belongs to the list.
const result = [
R.includes('oo', 'foo'),
R.includes({a: 1}, [{a: 1}])
]
// => [true, true ]
Try this R.includes example in Rambda REPL
import { _isArray } from './_internals/_isArray'
import { equals } from './equals'
export function includesArray(valueToFind, input){
let index = -1
while (++index < input.length){
if (equals(input[ index ], valueToFind)){
return true
}
}
return false
}
export function includes(valueToFind, input){
if (arguments.length === 1) return _input => includes(valueToFind, _input)
if (typeof input === 'string'){
return input.includes(valueToFind)
}
if (!input){
throw new TypeError(`Cannot read property \'indexOf\' of ${ input }`)
}
if (!_isArray(input)) return false
return includesArray(valueToFind, input)
}
import R from 'ramda'
import { includes } from './includes'
test('includes with string', () => {
const str = 'foo bar'
expect(includes('bar')(str)).toBeTrue()
expect(R.includes('bar')(str)).toBeTrue()
expect(includes('never', str)).toBeFalse()
expect(R.includes('never', str)).toBeFalse()
})
test('includes with array', () => {
const arr = [ 1, 2, 3 ]
expect(includes(2)(arr)).toBeTrue()
expect(R.includes(2)(arr)).toBeTrue()
expect(includes(4, arr)).toBeFalse()
expect(R.includes(4, arr)).toBeFalse()
})
test('with wrong input that does not throw', () => {
const result = includes(1, /foo/g)
const ramdaResult = R.includes(1, /foo/g)
expect(result).toBeFalse()
expect(ramdaResult).toBeFalse()
})
test('throws on wrong input - match ramda behaviour', () => {
expect(() => includes(2, null)).toThrowWithMessage(TypeError,
'Cannot read property \'indexOf\' of null')
expect(() => R.includes(2, null)).toThrowWithMessage(TypeError,
'Cannot read property \'indexOf\' of null')
expect(() => includes(2, undefined)).toThrowWithMessage(TypeError,
'Cannot read property \'indexOf\' of undefined')
expect(() => R.includes(2, undefined)).toThrowWithMessage(TypeError,
'Cannot read property \'indexOf\' of undefined')
})
It generates object with properties provided by condition and values provided by list array.
If condition is a function, then all list members are passed through it.
If condition is a string, then all list members are passed through R.path(condition).
const list = [ {id: 10}, {id: 20} ]
const withFunction = R.indexBy(
x => x.id,
list
)
const withString = R.indexBy(
'id',
list
)
const result = [
withFunction,
R.equals(withFunction, withString)
]
// => [ { 10: {id: 10}, 20: {id: 20} }, true ]
Try this R.indexBy example in Rambda REPL
It returns the index of the first element of list equals to valueToFind.
If there is no such element, it returns -1.
const list = [0, 1, 2, 3]
const result = [
R.indexOf(2, list),
R.indexOf(0, list)
]
// => [2, -1]
Try this R.indexOf example in Rambda REPL
init<T>(input: T[]): T[]
It returns all but the last element of list or string input.
const result = [
R.init([1, 2, 3]) ,
R.init('foo') // => 'fo'
]
// => [[1, 2], 'fo']
Try this R.init example in Rambda REPL
import baseSlice from './_internals/baseSlice'
export function init(listOrString){
if (typeof listOrString === 'string') return listOrString.slice(0, -1)
return listOrString.length ? baseSlice(
listOrString, 0, -1
) : []
}
import { init } from './init'
test('with array', () => {
expect(init([ 1, 2, 3 ])).toEqual([ 1, 2 ])
expect(init([ 1, 2 ])).toEqual([ 1 ])
expect(init([ 1 ])).toEqual([])
expect(init([])).toEqual([])
expect(init([])).toEqual([])
expect(init([ 1 ])).toEqual([])
})
test('with string', () => {
expect(init('foo')).toEqual('fo')
expect(init('f')).toEqual('')
expect(init('')).toEqual('')
})
interpolate(inputWithTags: string, templateArguments: object): string
It generages a new string from inputWithTags by replacing all {{x}} occurances with values provided by templateArguments.
const inputWithTags = 'foo is {{bar}} even {{a}} more'
const templateArguments = {"bar":"BAR", a: 1}
const result = R.interpolate(inputWithTags, templateArguments)
const expected = 'foo is BAR even 1 more'
// => `result` is equal to `expected`
Try this R.interpolate example in Rambda REPL
const getOccurances = input => input.match(/{{\s*.+?\s*}}/g)
const getOccuranceProp = occurance => occurance.replace(/{{\s*|\s*}}/g, '')
const replace = ({ inputHolder, prop, replacer }) => {
const regexBase = `{{${ prop }}}`
const regex = new RegExp(regexBase, 'g')
return inputHolder.replace(regex, replacer)
}
export function interpolate(input, templateInput){
if (arguments.length === 1){
return _templateInput => interpolate(input, _templateInput)
}
const occurances = getOccurances(input)
if (occurances === null) return input
let inputHolder = input
for (const occurance of occurances){
const prop = getOccuranceProp(occurance)
inputHolder = replace({
inputHolder,
prop,
replacer : templateInput[ prop ],
})
}
return inputHolder
}
import { interpolate } from './interpolate'
test('within bracets', () => {
const input = 'foo is { {{bar}} } even {{a}} more'
const templateInput = {
bar : 'BAR',
a : 1,
}
const result = interpolate(input, templateInput)
const expectedResult = 'foo is { BAR } even 1 more'
expect(result).toEqual(expectedResult)
})
test('happy', () => {
const input = 'foo is {{bar}} even {{a}} more'
const templateInput = {
bar : 'BAR',
a : 1,
}
const result = interpolate(input, templateInput)
const expectedResult = 'foo is BAR even 1 more'
expect(result).toEqual(expectedResult)
})
test('no interpolation + curry', () => {
const input = 'foo is bar even more'
const templateInput = { bar : 'BAR' }
const result = interpolate(input)(templateInput)
const expectedResult = 'foo is bar even more'
expect(result).toEqual(expectedResult)
})
test('with missing template input', () => {
const input = 'foo is {{bar}} even {{a}} more'
const templateInput = {
baz : 'BAR',
a : 1,
}
const result = interpolate(input, templateInput)
const expectedResult = 'foo is undefined even 1 more'
expect(result).toEqual(expectedResult)
})
test('with arbitrary expression', () => {
const input = '1 + 2 = {{ 1 + 2 }}'
const templateInput = {}
const result = interpolate(input, templateInput)
expect(result).toEqual(input)
})
It loops throw listA and listB and returns the intersection of the two according to R.equals.
const listA = [ { id : 1 }, { id : 2 }, { id : 3 }, { id : 4 } ]
const listB = [ { id : 3 }, { id : 4 }, { id : 5 }, { id : 6 } ]
const result = intersection(listA, listB)
// => [{ id : 3 }, { id : 4 }]
Try this R.intersection example in Rambda REPL
It adds a separator between members of list.
const list = [ 0, 1, 2, 3 ]
const separator = '|'
const result = intersperse(separator, list)
// => [0, '|', 1, '|', 2, '|', 3]
Try this R.intersperse example in Rambda REPL
It returns true if x is instance of targetPrototype.
const result = [
R.is(String, 'foo'),
R.is(Array, 1)
]
// => [true, false]
Try this R.is example in Rambda REPL
isEmpty<T>(x: T): boolean
It returns true if x is empty.
const result = [
R.isEmpty(''),
R.isEmpty({ x : 0 })
]
// => [true, false]
Try this R.isEmpty example in Rambda REPL
import { type } from './type'
export function isEmpty(input){
const inputType = type(input)
if ([ 'Undefined', 'NaN', 'Number', 'Null' ].includes(inputType))
return false
if (!input) return true
if (inputType === 'Object'){
return Object.keys(input).length === 0
}
if (inputType === 'Array'){
return input.length === 0
}
return false
}
import { isEmpty } from './isEmpty'
test('happy', () => {
expect(isEmpty(undefined)).toEqual(false)
expect(isEmpty('')).toEqual(true)
expect(isEmpty(null)).toEqual(false)
expect(isEmpty(' ')).toEqual(false)
expect(isEmpty(new RegExp(''))).toEqual(false)
expect(isEmpty([])).toEqual(true)
expect(isEmpty([ [] ])).toEqual(false)
expect(isEmpty({})).toEqual(true)
expect(isEmpty({ x : 0 })).toEqual(false)
expect(isEmpty(0)).toEqual(false)
expect(isEmpty(NaN)).toEqual(false)
expect(isEmpty([ '' ])).toEqual(false)
})
isFunction(input: any): boolean
It returns true if R.type of input is Async or Function.
const result = [
R.isFunction(R.mapAsync),
R.isFunction(R.add),
]
// => [true, true]
Try this R.isFunction example in Rambda REPL
import { type } from './type'
export function isFunction(fn){
return [ 'Async', 'Function' ].includes(type(fn))
}
import { isFunction } from './isFunction'
test('when function', () => {
const fn = () => {}
expect(isFunction(fn)).toEqual(true)
})
test('when promise', () => {
const fn = Promise.resolve(2)
expect(isFunction(fn)).toBeFalse()
})
test('when async', () => {
const fn = async x => x
expect(isFunction(fn)).toEqual(true)
})
test('when false', () => {
expect(isFunction(null)).toEqual(false)
})
isNil(x: any): x is null | undefined
It returns true if x is either null or undefined.
const result = [
R.isNil(null),
R.isNil(1),
]
// => [true, false]
Try this R.isNil example in Rambda REPL
export function isNil(x){
return x === undefined || x === null
}
import { isNil } from './isNil'
test('happy', () => {
expect(isNil(null)).toBeTrue()
expect(isNil(undefined)).toBeTrue()
expect(isNil([])).toBeFalse()
})
isPromise(input: any): boolean
isType(targetType: RambdaTypes, input: any): boolean
It returns true if targetType is equal to type of input according to R.type.
R.isType('Async',R.delay(1000))
// => true
Try this R.isType example in Rambda REPL
import { type } from './type'
export function isType(xType, x){
if (arguments.length === 1){
return xHolder => isType(xType, xHolder)
}
return type(x) === xType
}
import { isType } from './isType'
const list = [ 1, 2, 3 ]
test('array', () => {
expect(isType('Array', list)).toBeTruthy()
expect(isType('Array')([])).toBeTruthy()
})
test('promise', () => {
expect(isType('Promise', Promise.resolve(1))).toBeTruthy()
})
isValid({input: object, schema: Schema}: IsValid): boolean
It checks if input is following schema specifications.
If validation fails, it returns false.
Please check the detailed explanation as it is hard to write a short description for this method.
:boom: Independently, somebody else came with very similar idea called superstruct
const input = {a: ['foo', 'bar']}
const invalidInput = {a: ['foo', 'bar', 1]}
const schema = {a: [String]}
const result = [
R.isValid({schema, input}),
R.isValid({schema, input: invalidInput})
]
// => [true, false]
Try this R.isValid example in Rambda REPL
import { _isArray } from './_internals/_isArray'
import { all } from './all'
import { any } from './any'
import { includes } from './includes'
import { init } from './init'
import { test } from './test'
import { toLower } from './toLower'
import { type } from './type'
export function isPrototype(input){
const currentPrototype = input.prototype
const list = [ Number, String, Boolean, Promise ]
let toReturn = false
let counter = -1
while (++counter < list.length && !toReturn){
if (currentPrototype === list[ counter ].prototype) toReturn = true
}
return toReturn
}
export function prototypeToString(input){
const currentPrototype = input.prototype
const list = [ Number, String, Boolean, Promise ]
const translatedList = [ 'Number', 'String', 'Boolean', 'Promise' ]
let found
let counter = -1
while (++counter < list.length){
if (currentPrototype === list[ counter ].prototype) found = counter
}
return translatedList[ found ]
}
const typesWithoutPrototype = [ 'any', 'promise', 'async', 'function' ]
export function fromPrototypeToString(rule){
if (
_isArray(rule) ||
rule === undefined ||
rule === null ||
rule.prototype === undefined ||
typesWithoutPrototype.includes(rule)
){
return {
rule,
parsed : false,
}
}
if (String.prototype === rule.prototype){
return {
rule : 'string',
parsed : true,
}
}
if (Boolean.prototype === rule.prototype){
return {
rule : 'boolean',
parsed : true,
}
}
if (Number.prototype === rule.prototype){
return {
rule : 'number',
parsed : true,
}
}
return {
rule : type(rule.prototype).toLowerCase(),
parsed : true,
}
}
function getRuleAndType(schema, requirementRaw){
const ruleRaw = schema[ requirementRaw ]
const typeIs = type(ruleRaw)
const { rule, parsed } = fromPrototypeToString(ruleRaw)
return {
rule : rule,
ruleType : parsed ? 'String' : typeIs,
}
}
export function isValid({ input, schema }){
if (input === undefined || schema === undefined) return false
let flag = true
const boom = boomFlag => {
if (!boomFlag){
flag = false
}
}
for (const requirementRaw in schema){
if (flag){
const isOptional = requirementRaw.endsWith('?')
const requirement = isOptional ? init(requirementRaw) : requirementRaw
const { rule, ruleType } = getRuleAndType(schema, requirementRaw)
const inputProp = input[ requirement ]
const inputPropType = type(input[ requirement ])
const ok = isOptional && inputProp !== undefined || !isOptional
if (!ok || rule === 'any' && inputProp != null || rule === inputProp)
continue
if (ruleType === 'Object'){
/**
* This rule is standalone schema, so we recursevly call `isValid`
*/
const isValidResult = isValid({
input : inputProp,
schema : rule,
})
boom(isValidResult)
} else if (ruleType === 'String'){
/**
* Rule is actual rule such as 'number', so the two types are compared
*/
boom(toLower(inputPropType) === rule)
} else if (typeof rule === 'function'){
/**
* Rule is function so we pass to it the input
*/
boom(rule(inputProp))
} else if (ruleType === 'Array' && inputPropType === 'String'){
/**
* Enum case | rule is like a: ['foo', 'bar']
*/
boom(includes(inputProp, rule))
} else if (
ruleType === 'Array' &&
rule.length === 1 &&
inputPropType === 'Array'
){
/**
* 1. array of type | rule is like a: ['number']
* 2. rule is like a: [{foo: 'string', bar: 'number'}]
*/
const [ currentRule ] = rule
const currentRuleType = type(currentRule)
//Check if rule is invalid
boom(currentRuleType === 'String' ||
currentRuleType === 'Object' ||
isPrototype(currentRule))
if (currentRuleType === 'Object' && flag){
/**
* 2. rule is like a: [{from: 'string'}]
*/
const isValidResult = all(inputPropInstance =>
isValid({
input : inputPropInstance,
schema : currentRule,
}),
inputProp)
boom(isValidResult)
} else if (flag){
/**
* 1. array of type
*/
const actualRule =
currentRuleType === 'String' ?
currentRule :
prototypeToString(currentRule)
const isInvalidResult = any(inputPropInstance =>
type(inputPropInstance).toLowerCase() !==
actualRule.toLowerCase(),
inputProp)
boom(!isInvalidResult)
}
} else if (ruleType === 'RegExp' && inputPropType === 'String'){
boom(test(rule, inputProp))
} else {
boom(false)
}
}
}
return flag
}
import { delay } from './delay'
import { isPrototype, isValid } from './isValid'
test('is prototype', () => {
expect(isPrototype(Promise)).toBeTrue()
expect(isPrototype(Number)).toBeTrue()
expect(isPrototype(Boolean)).toBeTrue()
expect(isPrototype(String)).toBeTrue()
expect(isPrototype(0)).toBeFalse()
})
test('prototype inside array', () => {
const input = { a : [ 1, 2, 3, 4 ] }
const schema = { a : [ Number ] }
expect(isValid({
input,
schema,
})).toBeTruthy()
})
test('with Promise prototype', () => {
const input = { a : [ delay(1), delay(2) ] }
const schema = { a : [ Promise ] }
expect(isValid({
input,
schema,
})).toBeTruthy()
})
test('object prototype as rule - true', () => {
const input = { a : {} }
const schema = { a : Object }
expect(isValid({
input,
schema,
})).toBeTruthy()
})
test('list of functions', () => {
const input = { a : [ () => {}, delay ] }
const schema = { a : [ 'function' ] }
expect(isValid({
input,
schema,
})).toBeTruthy()
})
test('function schema type can be only string', () => {
const input = { a : [ () => {}, delay ] }
const schema = { a : [ Function ] }
expect(isValid({
input,
schema,
})).toBeFalsy()
})
test('object prototype as rule - false', () => {
const input = { a : null }
const schema = { a : Object }
expect(isValid({
input,
schema,
})).toBeFalsy()
})
test('number prototype as rule - true', () => {
const input = { a : 1 }
const schema = { a : Number }
expect(isValid({
input,
schema,
})).toBeTruthy()
})
test('array prototype as rule - true', () => {
const input = { a : [ 1, 2, 3 ] }
const schema = { a : Array }
expect(isValid({
input,
schema,
})).toBeTruthy()
})
test('array prototype as rule - false', () => {
const input = { a : null }
const schema = { a : Array }
expect(isValid({
input,
schema,
})).toBeFalsy()
})
test('string prototype as rule - true', () => {
const input = { a : 'foo' }
const schema = { a : String }
expect(isValid({
input,
schema,
})).toBeTruthy()
})
test('string prototype as rule - false', () => {
const input = { a : null }
const schema = { a : String }
expect(isValid({
input,
schema,
})).toBeFalsy()
})
test('boolean prototype as rule - true', () => {
const input = { a : true }
const schema = { a : Boolean }
expect(isValid({
input,
schema,
})).toBeTruthy()
})
test('boolean prototype as rule - false', () => {
const input = { a : null }
const schema = { a : Boolean }
expect(isValid({
input,
schema,
})).toBeFalsy()
})
test('regex prototype cannot be rule - true', () => {
const input = { a : /foo/g }
const schema = { a : new RegExp('foo') }
expect(isValid({
input,
schema,
})).toBeFalsy()
})
test('undefined as a rule - true', () => {
const input = { a : undefined }
const schema = { a : undefined }
expect(isValid({
input,
schema,
})).toBeTruthy()
})
test('undefined as a rule - false', () => {
const input = { a : null }
const schema = { a : undefined }
expect(isValid({
input,
schema,
})).toBeFalsy()
})
test('null as a rule - true', () => {
const input = { a : null }
const schema = { a : null }
expect(isValid({
input,
schema,
})).toBeTruthy()
})
test('null as a rule - false', () => {
const input = { a : undefined }
const schema = { a : null }
expect(isValid({
input,
schema,
})).toBeFalsy()
})
test('`any` safeguard against `null`', () => {
const input = { a : null }
const schema = { a : 'any' }
expect(isValid({
input,
schema,
})).toBeFalsy()
})
test('`any` safeguard against `undefined`', () => {
const input = { a : undefined }
const schema = { a : 'any' }
expect(isValid({
input,
schema,
})).toBeFalsy()
})
test('type can be `"any"`', () => {
const input = { a : () => {} }
const schema = { a : 'any' }
expect(isValid({
input,
schema,
})).toBeTruthy()
})
test('type can be `"function"`', () => {
const input = { a : () => {} }
const schema = { a : 'function' }
expect(isValid({
input,
schema,
})).toBeTruthy()
})
test('type can be `async`', () => {
const input = { a : async () => {} }
const schema = { a : 'async' }
expect(isValid({
input,
schema,
})).toBeTruthy()
})
test('type can be `promise`', () => {
const input = { a : delay(1999) }
const schema = { a : 'promise' }
expect(isValid({
input,
schema,
})).toBeTruthy()
})
test('type can be `promise` list', () => {
const input = { a : [ delay(1999) ] }
const schema = { a : [ 'promise' ] }
expect(isValid({
input,
schema,
})).toBeTruthy()
})
test('function as schema - false', () => {
const input = {
a : {
ab : () => true,
ac : 3,
},
c : [ 1, 2 ],
}
const schema = {
'a' : {
ab : /fo/,
ac : 'number',
},
'b?' : 'string',
'c' : [ 'number' ],
}
expect(isValid({
input,
schema,
})).toBeFalsy()
})
test('regex ok', () => {
const input = {
a : {
ab : 'foo',
ac : 3,
},
c : [ 1, 2 ],
}
const schema = {
'a' : {
ab : /fo/,
ac : 'number',
},
'b?' : 'string',
'c' : [ 'number' ],
}
expect(isValid({
input,
schema,
})).toBeTruthy()
})
test('regex !ok', () => {
const input = {
a : {
ab : 'foo',
ac : 3,
},
c : [ 1, 2 ],
}
const schema = {
'a' : {
ab : /ba/,
ac : 'number',
},
'b?' : 'string',
'c' : [ 'number' ],
}
expect(isValid({
input,
schema,
})).toBeFalsy()
})
test('optional props is missing', () => {
const input = {
a : {
ab : 'foo',
ac : 3,
},
c : [ 1, 2 ],
}
const schema = {
'a' : {
ab : 'string',
ac : 'number',
},
'b?' : 'string',
'c' : [ 'number' ],
}
expect(isValid({
input,
schema,
})).toBeTruthy()
})
test('optional props is wrong type', () => {
const input = {
a : {
ab : 'foo',
ac : 3,
},
b : [],
c : [ 1, 2 ],
}
const schema = {
'a' : {
ab : 'string',
ac : 'number',
},
'b?' : 'string',
'c' : [ 'number' ],
}
expect(isValid({
input,
schema,
})).toBeFalsy()
})
test('optional props - nested', () => {
const input = {
a : {
ab : 'foo',
ac : 3,
},
b : [],
c : [ 1, 2 ],
}
const schema = {
a : {
'ab' : 'string',
'ac?' : 'number',
},
b : 'array',
c : [ 'number' ],
}
expect(isValid({
input,
schema,
})).toBeTruthy()
})
test('optional props is missing - nested', () => {
const input = {
a : { ab : 'foo' },
b : [],
c : [ 1, 2 ],
}
const schema = {
a : {
'ab' : 'string',
'ac?' : 'number',
},
b : 'array',
c : [ 'number' ],
}
expect(isValid({
input,
schema,
})).toBeTruthy()
})
test('optional props is wrong type - nested', () => {
const input = {
a : {
ab : 'foo',
ac : 'bar',
},
b : [],
c : [ 1, 2 ],
}
const schema = {
a : {
'ab' : 'string',
'ac?' : 'number',
},
b : 'array',
c : [ 'number' ],
}
expect(isValid({
input,
schema,
})).toBeFalsy()
})
test('nested schema', () => {
const input = {
a : {
b : 'str',
c : 3,
d : 'str',
},
b : 'foo',
}
const schema = {
a : {
b : 'string',
c : 'number',
d : 'string',
},
b : 'string',
}
expect(isValid({
input,
schema,
})).toBeTruthy()
const invalidInputFirst = {
a : {
b : 'str',
c : 3,
d : 'str',
},
b : 5,
}
expect(isValid({
input : invalidInputFirst,
schema,
})).toBeFalsy()
const invalidInputSecond = {
a : {
b : 'str',
c : 'str',
d : 'str',
},
b : 5,
}
expect(isValid({
input : invalidInputSecond,
schema,
})).toBeFalsy()
const invalidInputThird = {
a : { b : 'str' },
b : 5,
}
expect(isValid({
input : invalidInputThird,
schema,
})).toBeFalsy()
})
test('array of type', () => {
const input = {
a : [ 1, 2 ],
b : 'foo',
}
const schema = {
a : [ 'number' ],
b : 'string',
}
expect(isValid({
input,
schema,
})).toBeTruthy()
const invalidInput = {
a : [ 1, '1' ],
b : 'foo',
}
expect(isValid({
input : invalidInput,
schema,
})).toBeFalsy()
})
test('function as rule', () => {
const input = {
a : [ 1, 2, 3, 4 ],
b : 'foo',
}
const invalidInput = {
a : [ 4 ],
b : 'foo',
}
const schema = {
a : x => x.length > 2,
b : 'string',
}
expect(isValid({
input,
schema,
})).toBeTruthy()
expect(isValid({
input : invalidInput,
schema,
})).toBeFalsy()
})
test('input prop is undefined', () => {
const input = { b : 3 }
const schema = { a : 'number' }
expect(isValid({
input,
schema,
})).toBeFalsy()
})
test('enum', () => {
const input = { a : 'foo' }
const invalidInput = { a : '' }
const schema = { a : [ 'foo', 'bar', 'baz' ] }
expect(isValid({
input,
schema,
})).toBeTruthy()
expect(isValid({
input : invalidInput,
schema,
})).toBeFalsy()
})
test('readme example', () => {
const basicSchema = { a : [ 'string' ] }
const schema = {
b : [ basicSchema ],
c : {
d : { e : 'boolean' },
f : 'array',
},
g : [ 'foo', 'bar', 'baz' ],
}
const input = {
b : [ { a : [ 'led', 'zeppelin' ] } ],
c : {
d : { e : true },
f : [ 'any', 1, null, 'value' ],
},
g : 'foo',
}
expect(isValid({
input,
schema,
})).toBeTruthy()
})
test('should allow additional properties', () => {
const input = {
title : 'You shook me',
year : 1969,
}
expect(isValid({
input,
schema : { title : 'string' },
})).toBeTruthy()
})
test('accepts values as schemas', () => {
const input = {
title : 'You shook me',
genre : 'Blues',
year : 1969,
}
const schema = {
title : 'You shook me',
year : 1969,
}
expect(isValid({
input,
schema,
})).toBeTruthy()
})
test('compatible schemas with nested object', () => {
const input = {
foo : 'bar',
baz : { a : { b : 'c' } },
}
const invalidInputFirst = {
foo : 'bar',
baz : { a : { b : 1 } },
}
const invalidInputSecond = {
foo : 'bar',
baz : { a : { b : [] } },
}
const invalidInputThird = {
foo : 'bar',
baz : { a : { b : null } },
}
const schema = {
foo : 'string',
baz : { a : { b : 'string' } },
}
expect(isValid({
input,
schema,
})).toBeTruthy()
expect(isValid({
input : invalidInputFirst,
schema,
})).toBeFalsy()
expect(isValid({
input : invalidInputSecond,
schema,
})).toBeFalsy()
expect(isValid({
input : invalidInputThird,
schema,
})).toBeFalsy()
})
test('should return true when schema is empty object', () => {
expect(isValid({
input : { a : 1 },
schema : {},
})).toBeTruthy()
})
test('when schema is undefined', () => {
expect(isValid({
input : { a : 1 },
schema : undefined,
})).toBeFalsy()
})
test('should return false with invalid schema rule', () => {
const input = {
foo : 'bar',
a : {},
}
const inputSecond = { foo : 'bar' }
const schema = {
foo : 'string',
baz : { a : {} },
}
expect(isValid({
input,
schema,
})).toBeFalsy()
expect(isValid({
input : inputSecond,
schema,
})).toBeFalsy()
})
test('array of schemas', () => {
const input = {
b : [
{
a : 'led',
b : 1,
},
{
a : 'dancing',
b : 1,
},
],
}
const basicSchema = {
a : String,
b : Number,
}
const schema = { b : [ basicSchema ] }
const result = isValid({
input,
schema,
})
expect(result).toBeTruthy()
})
isValidAsync(x: IsValidAsync): Promise<boolean>
Asynchronous version of R.isValid
const input = {a: 1, b: 2}
const invalidInput = {a: 1, b: 'foo'}
const schema = {a: Number, b: async x => {
await R.delay(100)
return typeof x === 'number'
}}
const result = await Promise.all([
R.isValidAsync({schema, input}),
R.isValidAsync({schema, input: invalidInput})
])
// => [true, false]
Try this R.isValidAsync example in Rambda REPL
import { forEach } from './forEach'
import { isPromise } from './isPromise'
import { isValid } from './isValid'
export async function isValidAsync({ schema, input }){
const asyncSchema = {}
const simpleSchema = {}
forEach((rule, prop) => {
if (isPromise(rule)){
asyncSchema[ prop ] = rule
} else {
simpleSchema[ prop ] = rule
}
}, schema)
if (Object.keys(asyncSchema).length === 0)
return isValid({
input,
schema,
})
if (
!isValid({
input,
schema : simpleSchema,
})
)
return false
let toReturn = true
for (const singleRuleProp in asyncSchema){
if (toReturn){
const validated = await asyncSchema[ singleRuleProp ](input[ singleRuleProp ])
if (!validated) toReturn = false
}
}
return toReturn
}
import { result } from 'lodash'
import { delay } from './delay'
import { isValidAsync } from './isValidAsync'
const simplePredicate = async x => {
await delay(100)
return x > 5
}
test('happy', async () => {
const input = {
a : 1,
b : 7,
c : 9,
additional : 'foo',
}
const invalidInput = {
a : 1,
b : 2,
c : 9,
}
const schema = {
a : Number,
b : simplePredicate,
c : simplePredicate,
}
const invalidSchema = {
a : Boolean,
b : simplePredicate,
c : simplePredicate,
}
const result = await isValidAsync({
input,
schema,
})
const invalidResult = await isValidAsync({
input,
schema : invalidSchema,
})
const withInvalidInput = await isValidAsync({
input : invalidInput,
schema,
})
expect(result).toBeTruthy()
expect(invalidResult).toBeFalsy()
expect(withInvalidInput).toBeFalsy()
})
test('without async rules', async () => {
const input = {
a : 1,
b : 7,
}
const schema = {
a : Number,
b : x => x > 2,
}
const invalidSchema = {
a : Number,
b : Boolean,
}
const result = await isValidAsync({
input,
schema,
})
const invalidResult = await isValidAsync({
input,
schema : invalidSchema,
})
expect(result).toBeTruthy()
expect(invalidResult).toBeFalsy()
})
test('readme example', async () => {
const input = {
a : 1,
b : 2,
}
const invalidInput = {
a : 1,
b : 'foo',
}
const schema = {
a : Number,
b : async x => {
await delay(100)
return typeof x === 'number'
},
}
const result = await Promise.all([
isValidAsync({
schema,
input,
}),
isValidAsync({
schema,
input : invalidInput,
}),
])
expect(result).toEqual([ true, false ])
})
join<T>(glue: string, list: T[]): string
It returns a string of all list instances joined with a glue.
R.join('-', [1, 2, 3]) // => '1-2-3'
Try this R.join example in Rambda REPL
export function join(glue, list){
if (arguments.length === 1) return _list => join(glue, _list)
return list.join(glue)
}
import { join } from './join'
test('curry', () => {
expect(join('|')([ 'foo', 'bar', 'baz' ])).toEqual('foo|bar|baz')
expect(join('|', [ 1, 2, 3 ])).toEqual('1|2|3')
const spacer = join(' ')
expect(spacer([ 'a', 2, 3.4 ])).toEqual('a 2 3.4')
})
keys<T extends object>(x: T): (keyof T)[]
It applies Object.keys over x and returns its keys.
R.keys({a:1, b:2}) // => ['a', 'b']
Try this R.keys example in Rambda REPL
export function keys(x){
return Object.keys(x)
}
import { keys } from './keys'
test('happy', () => {
expect(keys({ a : 1 })).toEqual([ 'a' ])
})
last(str: string): string
It returns the last element of input, as the input can be either a string or an array.
const result = [
R.last([1, 2, 3]),
R.last('foo'),
]
// => [3, 'o']
Try this R.last example in Rambda REPL
export function last(listOrString){
if (typeof listOrString === 'string'){
return listOrString[ listOrString.length - 1 ] || ''
}
return listOrString[ listOrString.length - 1 ]
}
import { last } from './last'
test('with list', () => {
expect(last([ 1, 2, 3 ])).toBe(3)
expect(last([])).toBeUndefined()
})
test('with string', () => {
expect(last('abc')).toEqual('c')
expect(last('')).toEqual('')
})
lastIndexOf<T>(target: T, list: T[]): number
It returns the last index of target in list array.
R.equals is used to determine equality between target and members of list.
If there is no such index, then -1 is returned.
const list = [1, 2, 3, 1, 2, 3]
const result = [
R.lastIndexOf(2, list),
R.lastIndexOf(4, list),
]
// => [4, -1]
Try this R.lastIndexOf example in Rambda REPL
import { equals } from './equals'
export function lastIndexOf(target, list){
if (arguments.length === 1) return _list => lastIndexOf(target, _list)
let index = list.length
while (--index > 0){
if (equals(list[ index ], target)){
return index
}
}
return -1
}
import { lastIndexOf } from './lastIndexOf'
test('happy', () => {
const a = lastIndexOf(1, [ 1, 2, 3, 1, 2 ])
const b = lastIndexOf(1)([ 1, 2, 3, 1, 2 ])
expect(a).toEqual(3)
expect(b).toEqual(3)
})
test('false', () => {
const a = lastIndexOf(10, [ 1, 2, 3, 1, 2 ])
expect(a).toEqual(-1)
})
length<T>(input: T[]): number
It returns the length property of list or string input.
const result = [
R.length([1, 2, 3, 4]),
R.length('foo'),
]
// => [4, 3]
Try this R.length example in Rambda REPL
export function length(x){
if (!x && x !== '' || x.length === undefined){
return NaN
}
return x.length
}
import { length } from './length'
test('happy', () => {
expect(length('foo')).toEqual(3)
expect(length([ 1, 2, 3 ])).toEqual(3)
expect(length([])).toEqual(0)
})
test('with empty string', () => {
expect(length('')).toEqual(0)
})
test('with bad input returns NaN', () => {
expect(length(0)).toBeNaN()
expect(length({})).toBeNaN()
expect(length(null)).toBeNaN()
expect(length(undefined)).toBeNaN()
})
lens<T, U, V>(getter: (s: T) => U, setter: (a: U, s: T) => V): Lens
It returns a lens for the given getter and setter functions.
The getter gets the value of the focus; the setter sets the value of the focus.
The setter should not mutate the data structure.
const xLens = R.lens(R.prop('x'), R.assoc('x'));
R.view(xLens, {x: 1, y: 2}) // => 1
R.set(xLens, 4, {x: 1, y: 2}) // => {x: 4, y: 2}
R.over(xLens, R.negate, {x: 1, y: 2}) // => {x: -1, y: 2}
Try this R.lens example in Rambda REPL
export function lens(getter, setter){
return function (functor){
return function (target){
return functor(getter(target)).map(focus => setter(focus, target))
}
}
}
lensEq<T, U>(lens: Lens, target: T, input: U): boolean
It returns true if data structure focused by the given lens equals to the target value.
R.equals is used to determine equality.
:boom: Idea for this method comes from
ramda-adjunctlibrary
const list = [ 1, 2, 3 ]
const lens = R.lensIndex(0)
const result = R.lensEq(
lens, 1, list
)
// => true
Try this R.lensEq example in Rambda REPL
import { curry } from './curry'
import { equals } from './equals'
import { view } from './view'
function lensEqFn(
lens, target, input
){
return equals(view(lens, input), target)
}
export const lensEq = curry(lensEqFn)
import { lensEq } from './lensEq'
import { lensIndex } from './lensIndex'
import { lensPath } from './lensPath'
test('with list', () => {
const list = [ 1, 2, 3 ]
const lens = lensIndex(0)
expect(lensEq(
lens, 1, list
)).toBeTrue()
expect(lensEq(lens, 2)(list)).toBeFalse()
})
test('with R.lensPath', () => {
const input = { a : { b : { c : 1 } } }
const target = { c : 1 }
const lens = lensPath('a.b')
expect(lensEq(lens)(target)(input)).toBeTrue()
expect(lensEq(
lens, target, { c : 2 }
)).toBeFalse()
})
lensIndex(index: number): Lens
It returns a lens that focuses on specified index.
const list = ['a', 'b', 'c']
const headLens = R.lensIndex(0)
R.view(headLens, list) // => 'a'
R.set(headLens, 'x', list) // => ['x', 'b', 'c']
R.over(headLens, R.toUpper, list) // => ['A', 'b', 'c']
Try this R.lensIndex example in Rambda REPL
import { lens } from './lens'
import { nth } from './nth'
import { update } from './update'
export function lensIndex(index){
return lens(nth(index), update(index))
}
import { compose } from './compose'
import { keys } from './keys'
import { lensIndex } from './lensIndex'
import { over } from './over'
import { set } from './set'
import { view } from './view'
const testList = [ { a : 1 }, { b : 2 }, { c : 3 } ]
test('focuses list element at the specified index', () => {
expect(view(lensIndex(0), testList)).toEqual({ a : 1 })
})
test('returns undefined if the specified index does not exist', () => {
expect(view(lensIndex(10), testList)).toEqual(undefined)
})
test('sets the list value at the specified index', () => {
expect(set(
lensIndex(0), 0, testList
)).toEqual([ 0, { b : 2 }, { c : 3 } ])
})
test('applies function to the value at the specified list index', () => {
expect(over(
lensIndex(2), keys, testList
)).toEqual([ { a : 1 }, { b : 2 }, [ 'c' ] ])
})
test('can be composed', () => {
const nestedList = [ 0, [ 10, 11, 12 ], 1, 2 ]
const composedLens = compose(lensIndex(1), lensIndex(0))
expect(view(composedLens, nestedList)).toEqual(10)
})
test('set s (get s) === s', () => {
expect(set(
lensIndex(0), view(lensIndex(0), testList), testList
)).toEqual(testList)
})
test('get (set s v) === v', () => {
expect(view(lensIndex(0), set(
lensIndex(0), 0, testList
))).toEqual(0)
})
test('get (set(set s v1) v2) === v2', () => {
expect(view(lensIndex(0),
set(
lensIndex(0), 11, set(
lensIndex(0), 10, testList
)
))).toEqual(11)
})
lensPath(path: RamdaPath): Lens
It returns a lens that focuses on specified path.
const lensPath = R.lensPath(['x', 0, 'y'])
const input = {x: [{y: 2, z: 3}, {y: 4, z: 5}]}
R.view(lensPath, input) // => 2
R.set(lensPath, 1, input)
// => {x: [{y: 1, z: 3}, {y: 4, z: 5}]}
R.over(xHeadYLens, R.negate, input)
// => {x: [{y: -2, z: 3}, {y: 4, z: 5}]}
Try this R.lensPath example in Rambda REPL
import {assocPath} from './assocPath'
import {lens} from './lens'
import {path} from './path'
export function lensPath(key) {
return lens(path(key), assocPath(key))
}
import { compose } from './compose'
import { identity } from './identity'
import { inc } from './inc'
import { lensPath } from './lensPath'
import { lensProp } from './lensProp'
import { over } from './over'
import { set } from './set'
import { view } from './view'
const testObj = {
a : [ { b : 1 }, { b : 2 } ],
d : 3,
}
test('view', () => {
expect(view(lensPath('d'), testObj)).toEqual(3)
expect(view(lensPath('a.0.b'), testObj)).toEqual(1)
// this is different to ramda, as ramda will return a clone of the input object
expect(view(lensPath(''), testObj)).toEqual(undefined)
})
test('set', () => {
expect(set(
lensProp('d'), 0, testObj
)).toEqual({
a : [ { b : 1 }, { b : 2 } ],
d : 0,
})
expect(set(
lensPath('a.0.b'), 0, testObj
)).toEqual({
a : [ { b : 0 }, { b : 2 } ],
d : 3,
})
expect(set(
lensPath('a.0.X'), 0, testObj
)).toEqual({
a : [
{
b : 1,
X : 0,
},
{ b : 2 },
],
d : 3,
})
expect(set(
lensPath([]), 0, testObj
)).toEqual(0)
})
test('over', () => {
expect(over(
lensPath('d'), inc, testObj
)).toEqual({
a : [ { b : 1 }, { b : 2 } ],
d : 4,
})
expect(over(
lensPath('a.1.b'), inc, testObj
)).toEqual({
a : [ { b : 1 }, { b : 3 } ],
d : 3,
})
expect(over(
lensProp('X'), identity, testObj
)).toEqual({
a : [ { b : 1 }, { b : 2 } ],
d : 3,
X : undefined,
})
expect(over(
lensPath('a.0.X'), identity, testObj
)).toEqual({
a : [
{
b : 1,
X : undefined,
},
{ b : 2 },
],
d : 3,
})
})
test('compose', () => {
const composedLens = compose(lensPath('a'), lensPath('1.b'))
expect(view(composedLens, testObj)).toEqual(2)
})
test('set s (get s) === s', () => {
expect(set(
lensPath([ 'd' ]), view(lensPath([ 'd' ]), testObj), testObj
)).toEqual(testObj)
expect(set(
lensPath([ 'a', 0, 'b' ]),
view(lensPath([ 'a', 0, 'b' ]), testObj),
testObj
)).toEqual(testObj)
})
test('get (set s v) === v', () => {
expect(view(lensPath([ 'd' ]), set(
lensPath([ 'd' ]), 0, testObj
))).toEqual(0)
expect(view(lensPath([ 'a', 0, 'b' ]), set(
lensPath([ 'a', 0, 'b' ]), 0, testObj
))).toEqual(0)
})
test('get (set(set s v1) v2) === v2', () => {
const p = [ 'd' ]
const q = [ 'a', 0, 'b' ]
expect(view(lensPath(p), set(
lensPath(p), 11, set(
lensPath(p), 10, testObj
)
))).toEqual(11)
expect(view(lensPath(q), set(
lensPath(q), 11, set(
lensPath(q), 10, testObj
)
))).toEqual(11)
})
lensProp(prop: string): {
<T, U>(obj: T): U
It returns a lens that focuses on specified property prop.
const xLens = R.lensProp('x');
const input = {x: 1, y: 2}
R.view(xLens, input) // => 1
R.set(xLens, 4, input)
// => {x: 4, y: 2}
R.over(xLens, R.negate, input)
// => {x: -1, y: 2}
Try this R.lensProp example in Rambda REPL
import { assoc } from './assoc'
import { lens } from './lens'
import { prop } from './prop'
export function lensProp(key){
return lens(prop(key), assoc(key))
}
import { compose } from './compose'
import { identity } from './identity'
import { inc } from './inc'
import { lensProp } from './lensProp'
import { over } from './over'
import { set } from './set'
import { view } from './view'
const testObj = {
a : 1,
b : 2,
c : 3,
}
test('focuses object the specified object property', () => {
expect(view(lensProp('a'), testObj)).toEqual(1)
})
test('returns undefined if the specified property does not exist', () => {
expect(view(lensProp('X'), testObj)).toEqual(undefined)
})
test('sets the value of the object property specified', () => {
expect(set(
lensProp('a'), 0, testObj
)).toEqual({
a : 0,
b : 2,
c : 3,
})
})
test('adds the property to the object if it doesn\'t exist', () => {
expect(set(
lensProp('d'), 4, testObj
)).toEqual({
a : 1,
b : 2,
c : 3,
d : 4,
})
})
test('applies function to the value of the specified object property', () => {
expect(over(
lensProp('a'), inc, testObj
)).toEqual({
a : 2,
b : 2,
c : 3,
})
})
test('applies function to undefined and adds the property if it doesn\'t exist', () => {
expect(over(
lensProp('X'), identity, testObj
)).toEqual({
a : 1,
b : 2,
c : 3,
X : undefined,
})
})
test('can be composed', () => {
const nestedObj = {
a : { b : 1 },
c : 2,
}
const composedLens = compose(lensProp('a'), lensProp('b'))
expect(view(composedLens, nestedObj)).toEqual(1)
})
test('set s (get s) === s', () => {
expect(set(
lensProp('a'), view(lensProp('a'), testObj), testObj
)).toEqual(testObj)
})
test('get (set s v) === v', () => {
expect(view(lensProp('a'), set(
lensProp('a'), 0, testObj
))).toEqual(0)
})
test('get (set(set s v1) v2) === v2', () => {
expect(view(lensProp('a'),
set(
lensProp('a'), 11, set(
lensProp('a'), 10, testObj
)
))).toEqual(11)
})
lensSatisfies<T, U>(predicate: (x: T) => boolean, lens: Lens, input: U): boolean
It returns true if data structure focused by the given lens satisfies the predicate.
:boom: Idea for this method comes from
ramda-adjunctlibrary
const fn = R.lensSatisfies(x => x > 5, R.lensIndex(0))
const result = [
fn([10, 20, 30]),
fn([1, 2, 3]),
]
// => [true, false]
Try this R.lensSatisfies example in Rambda REPL
import { curry } from './curry'
import { view } from './view'
function lensSatisfiesFn(
predicate, lens, input
){
return Boolean(predicate(view(lens, input)))
}
export const lensSatisfies = curry(lensSatisfiesFn)
import { lensIndex } from './lensIndex'
import { lensPath } from './lensPath'
import { lensSatisfies } from './lensSatisfies'
const predicate = x => x > 1
test('with list', () => {
const lens = lensIndex(0)
const fn = lensSatisfies(predicate, lens)
expect(fn([ 10, 20, 30 ])).toBeTrue()
expect(fn([ 1, 2, 3 ])).toBeFalse()
})
test('with R.lensPath', () => {
const input1 = { a : { b : 10 } }
const input2 = { a : { b : 1 } }
const lens = lensPath('a.b')
const fn = lensSatisfies(predicate, lens)
expect(fn(input1)).toBeTrue()
expect(fn(input2)).toBeFalse()
})
map<T, U>(fn: ObjectIterator<T, U>, iterable: Dictionary<T>): Dictionary<U>
It returns the result of looping through iterable with fn.
It works with both array and object.
:boom: Unlike Ramda's
map, here property and input object are passed as arguments tofn, wheniterableis an object.
const fn = x => x * 2
const fnWhenObject = (val, prop)=>{
return `${prop}-${val}`
}
const iterable = [1, 2]
const obj = {a: 1, b: 2}
const result = [
R.map(fn, list),
R.map(fnWhenObject, obj)
]
// => [ [1, 4], {a: 'a-1', b: 'b-2'}]
Try this R.map example in Rambda REPL
import { _isArray } from './_internals/_isArray'
import { _keys } from './_internals/_keys'
export function mapArray(
fn, list, isIndexed = false
){
let index = 0
const willReturn = Array(list.length)
while (index < list.length){
willReturn[ index ] = isIndexed ? fn(list[ index ], index) : fn(list[ index ])
index++
}
return willReturn
}
export function mapObject(fn, obj){
let index = 0
const keys = _keys(obj)
const len = keys.length
const willReturn = {}
while (index < len){
const key = keys[ index ]
willReturn[ key ] = fn(
obj[ key ], key, obj
)
index++
}
return willReturn
}
export const mapObjIndexed = mapObject
export function map(fn, list){
if (arguments.length === 1) return _list => map(fn, _list)
if (list === undefined) return []
if (_isArray(list)) return mapArray(fn, list)
return mapObject(fn, list)
}
import { map } from './map'
const double = x => x * 2
describe(`with array`, () => {
test('happy', () => {
expect(map(double, [ 1, 2, 3 ])).toEqual([ 2, 4, 6 ])
})
test('when undefined instead of array', () => {
/**
* https://github.com/selfrefactor/rambda/issues/77
*/
expect(map(double)(undefined)).toEqual([])
})
})
describe(`with object`, () => {
const obj = {
a : 1,
b : 2,
}
test('happy', () => {
expect(map(double, obj)).toEqual({
a : 2,
b : 4,
})
})
test('property as second and input object as third argument', () => {
const obj = {
a : 1,
b : 2,
}
const iterator = (
val, prop, inputObject
) => {
expect(prop).toBeString()
expect(inputObject).toEqual(obj)
return val * 2
}
expect(map(iterator)(obj)).toEqual({
a : 2,
b : 4,
})
})
})
mapArray<T>(fn: Iterator<T, T>, iterable: T[]): T[]
const result = R.mapArray(x => x + 1, [1, 2])
// => [2, 3]
Try this R.mapArray example in Rambda REPL
mapAsync<T, K>(fn: AsyncIterable<T, K>, list: T[]): Promise<K[]>
Sequential asynchronous mapping with fn over members of list.
async function fn(x){
await R.delay(1000)
return x+1
}
const result = R.mapAsync(fn, [1, 2, 3])
// `result` resolves after 3 seconds to `[2, 3, 4]`
Try this R.mapAsync example in Rambda REPL
import { _isArray } from './_internals/_isArray'
async function mapAsyncFn(fn, listOrObject){
if (_isArray(listOrObject)){
const willReturn = []
let i = 0
for (const a of listOrObject){
willReturn.push(await fn(a, i++))
}
return willReturn
}
const willReturn = {}
for (const prop in listOrObject){
willReturn[ prop ] = await fn(listOrObject[ prop ], prop)
}
return willReturn
}
export function mapAsync(fn, listOrObject){
if (arguments.length === 1){
return async _listOrObject => mapAsyncFn(fn, _listOrObject)
}
return new Promise((resolve, reject) => {
mapAsyncFn(fn, listOrObject).then(resolve)
.catch(reject)
})
}
import { composeAsync } from './composeAsync'
import { delay } from './delay'
import { map } from './map'
import { mapAsync } from './mapAsync'
const rejectDelay = a =>
new Promise((_, reject) => {
setTimeout(() => {
reject(a + 20)
}, 100)
})
test('happy', async () => {
const fn = async (x, prop) => {
await delay(100)
expect(prop).toBeNumber()
return x + 1
}
const result = await mapAsync(fn, [ 1, 2, 3 ])
expect(result).toEqual([ 2, 3, 4 ])
})
test('with object', async () => {
const fn = async (x, prop) => {
expect(prop).toBeString()
return x + 1
}
const result = await mapAsync(fn, {
a : 1,
b : 2,
})
expect(result).toEqual({
a : 2,
b : 3,
})
})
test('with R.composeAsync', async () => {
const result = await composeAsync(
map(x => x + 1),
mapAsync(async x => {
delay(x)
return x
}),
map(x => x * 10)
)([ 1, 2, 3 ])
expect(result).toEqual([ 11, 21, 31 ])
})
test('error', async () => {
try {
await mapAsync(rejectDelay)([ 1, 2, 3 ])
} catch (err){
expect(err).toBe(21)
}
})
mapAsyncLimit<T, K>(fn: AsyncIterable<T, K>, limit: number, list: T[]): Promise<K[]>
It is similar to R.mapFastAsync in that it uses Promise.all but not over the whole list, rather than with only slice from list with length limit.
:boom: For example usage, please check
R.mapAsyncLimittests.
import { mapFastAsync, mapFastAsyncFn } from './mapFastAsync'
import { splitEvery } from './splitEvery'
async function mapAsyncLimitFn(
iterable, limit, list
){
if (list.length < limit) return mapFastAsync(iterable, list)
const slices = splitEvery(limit, list)
let toReturn = []
for (const slice of slices){
const iterableResult = await mapFastAsyncFn(iterable, slice)
toReturn = [ ...toReturn, ...iterableResult ]
}
return toReturn
}
export function mapAsyncLimit(
iterable, limit, list
){
if (arguments.length === 2){
return async _list => mapAsyncLimitFn(
iterable, limit, _list
)
}
return new Promise((resolve, reject) => {
mapAsyncLimitFn(
iterable, limit, list
).then(resolve)
.catch(reject)
})
}
import isCI from 'is-ci'
import { composeAsync } from './composeAsync'
import { delay } from './delay'
import { mapAsync } from './mapAsync'
import { mapAsyncLimit } from './mapAsyncLimit'
import { toDecimal } from './toDecimal'
jest.setTimeout(30000)
test('happy', async () => {
const limit = 3
const startTime = new Date().getTime()
const list = [ 1, 2, 3, 4, 5, 6, 7, 8, 9 ]
const iterable = async x => {
await delay(500)
return x + 1
}
const result = await mapAsyncLimit(
iterable, limit, list
)
const endTime = new Date().getTime()
const diffTime = endTime - startTime
const startTime2 = new Date().getTime()
await mapAsync(iterable, list)
const endTime2 = new Date().getTime()
const diffTime2 = endTime2 - startTime2
const methodScale = toDecimal((diffTime2 - diffTime) / 1000, 0)
expect(result).toEqual([ 2, 3, 4, 5, 6, 7, 8, 9, 10 ])
if (!isCI) expect(methodScale).toBe(limit)
})
const fn = async x => {
await delay(100)
return x + 1
}
test('with R.composeAsync', async () => {
const result = await composeAsync(mapAsyncLimit(fn, 2), x =>
x.map(xx => xx + 1))([ 1, 2, 3, 4, 5, 6 ])
expect(result).toEqual([ 3, 4, 5, 6, 7, 8 ])
})
test('fallback to R.mapFastAsync', async () => {
const result = await mapAsyncLimit(
fn, 4, [ 1, 2, 3 ]
)
expect(result).toEqual([ 2, 3, 4 ])
})
mapFastAsync<T, K>(fn: AsyncIterable<T, K>, list: T[]): Promise<K[]>
Parrallel asynchronous mapping with fn over members of list.
async function fn(x){
await R.delay(1000)
return x+1
}
const result = R.mapFastAsync(fn, [1, 2, 3])
// `result` resolves after 1 second to `[2, 3, 4]`
Try this R.mapFastAsync example in Rambda REPL
export async function mapFastAsyncFn(fn, arr){
const promised = arr.map((a, i) => fn(a, i))
return Promise.all(promised)
}
export function mapFastAsync(fn, arr){
if (arguments.length === 1){
return async holder => mapFastAsyncFn(fn, holder)
}
return new Promise((resolve, reject) => {
mapFastAsyncFn(fn, arr).then(resolve)
.catch(reject)
})
}
import { composeAsync } from './composeAsync'
import { delay } from './delay'
import { map } from './map'
import { mapFastAsync } from './mapFastAsync'
test('happy', async () => {
const fn = async x => {
await delay(100)
return x + 10
}
const result = await mapFastAsync(fn, [ 1, 2, 3 ])
const curriedResult = await mapFastAsync(fn)([ 1, 2, 3 ])
expect(result).toEqual([ 11, 12, 13 ])
expect(curriedResult).toEqual([ 11, 12, 13 ])
})
test('composeAsync', async () => {
const result = await composeAsync(
mapFastAsync(async x => {
await delay(100)
return x + 1
}),
mapFastAsync(async x => {
await delay(100)
return x + 10
}),
map(x => x * 10)
)([ 1, 2, 3 ])
expect(result).toEqual([ 21, 31, 41 ])
})
test('error', async () => {
try {
const fn = async x => {
JSON.parse('{:')
}
const result = await mapFastAsync(fn, [ 1, 2, 3 ])
} catch (err){
expect(err.message).toBe('Unexpected token : in JSON at position 1')
}
})
test('pass index as second argument', async () => {
await mapFastAsync((x, i) => {
expect(x % 10).toBe(0)
expect(typeof i).toBe('number')
},
[ 10, 20, 30 ])
})
Same as R.map, but it passes index as second argument to the iterator, when looping over arrays.
mapKeys<T, U>(changeKeyFn: (x: string) => string, obj: { [key: string]: T}): U
It takes an object and returns a new object with changed keys according to changeKeyFn function.
const obj = {a: 1, b: 2}
const changeKeyFn = prop => `{prop}_foo`
const result = R.mapKeys(changeKeyFn, obj)
// => {a_foo: 1, b_foo: 2}
Try this R.mapKeys example in Rambda REPL
export function mapKeys(changeKeyFn, obj){
if (arguments.length === 1) return _obj => mapKeys(changeKeyFn, _obj)
const toReturn = {}
Object.keys(obj).forEach(prop => toReturn[ changeKeyFn(prop) ] = obj[ prop ])
return toReturn
}
import { mapKeys } from './mapKeys'
const obj = {
a : 1,
b : 2,
}
const changeKeyFn = prop => `${ prop }_foo`
const expected = {
a_foo : 1,
b_foo : 2,
}
test('happy', () => {
const result = mapKeys(changeKeyFn, obj)
expect(result).toEqual(expected)
})
test('curried', () => {
const result = mapKeys(changeKeyFn)(obj)
expect(result).toEqual(expected)
})
mapObject<T>(fn: ObjectIterator<T, T>, iterable: Dictionary<T>): Dictionary<T>
const result = R.mapObject(x => x + 1, {a:1, b:2})
// => {a:2, b:3}
Try this R.mapObject example in Rambda REPL
It works the same way as R.map does for objects. It is added as Ramda also has this method.
const fn = (val, prop) => {
return `${prop}-${val}`
}
const obj = {a: 1, b: 2}
const result = R.map(mapObjIndexed, obj)
// => {a: 'a-1', b: 'b-2'}
Try this R.mapObjIndexed example in Rambda REPL
mapToObject<T, U>(fn: (input: T) => object|false, list: T[]): U
This method allows to generate an object from a list using input function fn.
This function must return either an object or false for every member of list input.
If false is returned, then this element of list will be skipped in the calculation of the result.
All of returned objects will be merged to generate the final result.
const list = [1, 2, 3, 12]
const fn = x => {
if(x > 10) return false
return x % 2 ? {[x]: x + 1}: {[x]: x + 10}
}
const result = mapToObject(fn, list)
const expected = {'1': 2, '2': 12, '3': 4}
// => `result` is equal to `expected`
Try this R.mapToObject example in Rambda REPL
import { map } from './map'
import { mergeAll } from './mergeAll'
import { ok } from './ok'
import { type } from './type'
export function mapToObject(fn, list){
if (arguments.length === 1){
return listHolder => mapToObject(fn, listHolder)
}
ok(type(fn), type(list))('Function', 'Array')
return mergeAll(map(fn, list))
}
import { mapToObject } from './mapToObject'
const list = [ 1, 2, 3 ]
const fn = x => x % 2 ? { [ x ] : x + 1 } : { [ x ] : x + 10 }
const expected = {
1 : 2,
2 : 12,
3 : 4,
}
test('happy', () => {
const result = mapToObject(fn, list)
expect(result).toEqual(expected)
})
test('curried', () => {
const result = mapToObject(fn)(list)
expect(result).toEqual(expected)
})
test('string.fn test', () => {
const list = [ 'auto', 'bar=false', 'foo', 'baz=1.5', 's=more', 'k=2' ]
const fn = x => {
const [ key, value ] = x.split('=')
if (value === undefined || value === 'true'){
return { [ key ] : true }
}
if (value === 'false'){
return { [ key ] : false }
}
if (Number.isNaN(Number(value))){
return { [ key ] : value }
}
return { [ key ] : Number(value) }
}
const expectedResult = {
auto : true,
foo : true,
bar : false,
baz : 1.5,
s : 'more',
k : 2,
}
const result = mapToObject(fn, list)
expect(result).toEqual(expectedResult)
})
test('bad path', () => {
expect(() => mapToObject(1, null)).toThrow()
})
mapToObjectAsync<T, U>(fn: (input: T) => Promise<object|false>, list: T[]): Promise<U>
Asynchronous version of R.mapToObject
import { mapAsync } from './mapAsync'
export async function mapToObjectAsyncFn(fn, list){
let toReturn = {}
const innerIterable = async x => {
const intermediateResult = await fn(x)
if (intermediateResult === false) return
toReturn = {
...toReturn,
...intermediateResult,
}
}
await mapAsync(innerIterable, list)
return toReturn
}
export function mapToObjectAsync(fn, list){
if (arguments.length === 1){
return async _list => mapToObjectAsyncFn(fn, _list)
}
return new Promise((resolve, reject) => {
mapToObjectAsyncFn(fn, list).then(resolve)
.catch(reject)
})
}
import { composeAsync } from './composeAsync'
import { delay } from './delay'
import { mapToObjectAsync } from './mapToObjectAsync'
const list = [ 1, 2, 3, 12 ]
const fn = async x => {
await delay(100)
if (x > 10) return false
return x % 2 ? { [ `key${ x }` ] : x + 1 } : { [ `key${ x }` ] : x + 10 }
}
const expected = {
key1 : 2,
key2 : 12,
key3 : 4,
}
test('happy', async () => {
const result = await mapToObjectAsync(fn, list)
expect(result).toEqual(expected)
})
test('with R.composeAsync', async () => {
const result = await composeAsync(mapToObjectAsync(fn), x =>
x.filter(xx => xx > 1))(list)
expect(result).toEqual({
key2 : 12,
key3 : 4,
})
})
match(regExpression: RegExp, str: string): string[]
Curried version of String.prototype.match which returns empty array, when there is no match.
const result = [
R.match('a', 'foo'),
R.match(/([a-z]a)/g, 'bananas')
]
// => [[], ['ba', 'na', 'na']]
Try this R.match example in Rambda REPL
export function match(pattern, input){
if (arguments.length === 1) return _input => match(pattern, _input)
const willReturn = input.match(pattern)
return willReturn === null ? [] : willReturn
}
import { equals } from './equals'
import { match } from './match'
test('happy', () => {
expect(match(/a./g)('foo bar baz')).toEqual([ 'ar', 'az' ])
})
test('fallback', () => {
expect(match(/a./g)('foo')).toEqual([])
})
test('with string', () => {
expect(match('a', 'foo')).toEqual([])
expect(equals(match('o', 'foo'), [ 'o' ])).toBeTrue()
})
test('throwing', () => {
expect(() => {
match(/a./g, null)
}).toThrowWithMessage(TypeError, 'Cannot read property \'match\' of null')
})
R.mathMod behaves like the modulo operator should mathematically, unlike the % operator (and by extension, R.modulo). So while -17 % 5 is -2, mathMod(-17, 5) is 3.
:boom: Explanation is taken from
Ramdadocumentation site.
const result = [
R.mathMod(-17, 5),
R.mathMod(17, 5),
R.mathMod(17, -5),
R.mathMod(17, 0)
]
// => [3, 2, NaN, NaN]
Try this R.mathMod example in Rambda REPL
max<T extends Ord>(x: T, y: T): T
It returns the greater value between x and y.
const result = [
R.max(5, 7),
R.max('bar', 'foo'),
]
// => [7, 'foo']
Try this R.max example in Rambda REPL
export function max(x, y){
if (arguments.length === 1) return _y => max(x, _y)
return y > x ? y : x
}
import { max } from './max'
test('with number', () => {
expect(max(2, 1)).toBe(2)
})
test('with string', () => {
expect(max('foo')('bar')).toBe('foo')
expect(max('bar')('baz')).toBe('baz')
})
maxBy<T>(compareFn: (input: T) => Ord, x: T, y: T): T
It returns the greater value between x and y according to compareFn function.
const compareFn = Math.abs
R.maxBy(compareFn, 5, -7) // => -7
Try this R.maxBy example in Rambda REPL
import { curry } from './curry'
export function maxByFn(
compareFn, x, y
){
return compareFn(y) > compareFn(x) ? y : x
}
export const maxBy = curry(maxByFn)
import { maxBy } from './maxBy'
test('happy', () => {
expect(maxBy(
Math.abs, -5, 2
)).toEqual(-5)
})
test('curried', () => {
expect(maxBy(Math.abs)(2, -5)).toEqual(-5)
expect(maxBy(Math.abs)(2)(-5)).toEqual(-5)
})
maybe<T>(ifRule: boolean, whenIf: T | Func<T>, whenElse: T | Func<T>): T
It acts as ternary operator and it is helpful when we have nested ternaries.
All of the inputs can be either direct values or anonymous functions. This is helpful if we don't want to evaluate certain paths as we can wrap this logic in a function.
const x = 4
const y = 8
const ifRule = x > 2
const whenIf = y > 10 ? 3 : 7
const whenElse = () => {
// just to show that it won't be evaluated
return JSON.parse('{a:')
}
const result = R.maybe(
ifRule,
whenIf,
whenElse,
)
// `result` is `7`
Try this R.maybe example in Rambda REPL
import { type } from './type'
export function maybe(
ifRule, whenIf, whenElse
){
const whenIfInput =
ifRule && type(whenIf) === 'Function' ? whenIf() : whenIf
const whenElseInput =
!ifRule && type(whenElse) === 'Function' ? whenElse() : whenElse
return ifRule ? whenIfInput : whenElseInput
}
import { maybe } from './maybe'
const WHEN_IF = 'WHEN_IF'
const WHEN_ELSE = 'WHEN_ELSE'
test('prevent type error', () => {
const x = 5
const y = null
const ifRule = x > 3
const result = maybe(
ifRule, WHEN_IF, () => y.a === 'foo'
)
expect(result).toBe(WHEN_IF)
})
test('whenElse is a function', () => {
const x = 2
const y = { a : 1 }
const ifRule = x > 3
const result = maybe(
ifRule, WHEN_IF, () => y.a === 'foo'
)
expect(result).toBeFalse()
})
test('whenIf', () => {
const x = 5
const ifRule = x > 3
const result = maybe(
ifRule, WHEN_IF, WHEN_ELSE
)
expect(result).toBe(WHEN_IF)
})
test('whenIf is a function', () => {
const x = 5
const ifRule = () => x > 3
const result = maybe(
ifRule, () => WHEN_IF, WHEN_ELSE
)
expect(result).toBe(WHEN_IF)
})
test('whenElse', () => {
const x = 1
const ifRule = x > 3
const result = maybe(
ifRule, WHEN_IF, WHEN_ELSE
)
expect(result).toBe(WHEN_ELSE)
})
mean(list: number[]): number
It returns the mean value of list input.
R.mean([ 2, 7 ])
// => 4.5
Try this R.mean example in Rambda REPL
import { sum } from './sum'
export function mean(list){
return sum(list) / list.length
}
import { mean } from './mean'
test('happy', () => {
expect(mean([ 2, 7 ])).toBe(4.5)
})
test('with NaN', () => {
expect(mean([])).toBeNaN()
})
median(list: number[]): number
It returns the median value of list input.
R.median([ 7, 2, 10, 9 ]) // => 8
Try this R.median example in Rambda REPL
import { mean } from './mean'
export function median(list){
const len = list.length
if (len === 0) return NaN
const width = 2 - len % 2
const idx = (len - width) / 2
return mean(Array.prototype.slice
.call(list, 0)
.sort((a, b) => {
if (a === b) return 0
return a < b ? -1 : 1
})
.slice(idx, idx + width))
}
import { median } from './median'
test('happy', () => {
expect(median([ 2 ])).toEqual(2)
expect(median([ 7, 2, 10, 2, 9 ])).toEqual(7)
})
test('with empty array', () => {
expect(median([])).toBeNaN()
})
memoize<T, K extends any[]>(fn: (...inputs: K) => T): (...inputs: K) => T
When fn is called for a second time with the same input, then the cache result is returned instead of calling again fn.
let result = 0
const fn = (a,b) =>{
result++
return a + b
}
const memoized = R.memoize(fn)
memoized(1, 2)
memoized(1, 2)
// => `result` is equal to `1`
Try this R.memoize example in Rambda REPL
import { compose } from './compose'
import { map } from './map'
import { replace } from './replace'
import { sort } from './sort'
import { take } from './take'
import { type } from './type'
const cache = {}
const normalizeObject = obj => {
const sortFn = (a, b) => a > b ? 1 : -1
const willReturn = {}
compose(map(prop => willReturn[ prop ] = obj[ prop ]),
sort(sortFn))(Object.keys(obj))
return willReturn
}
const stringify = a => {
if (type(a) === 'String'){
return a
} else if ([ 'Function', 'Async' ].includes(type(a))){
const compacted = replace(
/\s{1,}/g, ' ', a.toString()
)
return replace(
/\s/g, '_', take(15, compacted)
)
} else if (type(a) === 'Object'){
return JSON.stringify(normalizeObject(a))
}
return JSON.stringify(a)
}
const generateProp = (fn, ...inputArguments) => {
let propString = ''
inputArguments.forEach(inputArgument => {
propString += `${ stringify(inputArgument) }_`
})
return `${ propString }${ stringify(fn) }`
}
// with weakmaps
export function memoize(fn, ...inputArguments){
if (arguments.length === 1){
return (...inputArgumentsHolder) => memoize(fn, ...inputArgumentsHolder)
}
const prop = generateProp(fn, ...inputArguments)
if (prop in cache) return cache[ prop ]
if (type(fn) === 'Async'){
return new Promise(resolve => {
fn(...inputArguments).then(result => {
cache[ prop ] = result
resolve(result)
})
})
}
const result = fn(...inputArguments)
cache[ prop ] = result
return result
}
import { memoize } from './memoize'
test('memoize function without input arguments', () => {
const fn = () => 4
const memoized = memoize(fn)
expect(typeof memoized()).toBe('function')
})
test('happy', () => {
let counter = 0
const fn = ({ a, b, c }) => {
counter++
return a + b - c
}
const memoized = memoize(fn)
expect(memoized({
a : 1,
c : 3,
b : 2,
})).toBe(0)
expect(counter).toBe(1)
expect(memoized({
c : 3,
a : 1,
b : 2,
})).toBe(0)
expect(counter).toBe(1)
})
test('normal function', () => {
let counter = 0
const fn = (a, b) => {
counter++
return a + b
}
const memoized = memoize(fn)
expect(memoized(1, 2)).toBe(3)
expect(memoized(1, 2)).toBe(3)
expect(memoized(1, 2)).toBe(3)
expect(counter).toBe(1)
expect(memoized(2, 2)).toBe(4)
expect(counter).toBe(2)
expect(memoized(1, 2)).toBe(3)
expect(counter).toBe(2)
})
test('async function', async () => {
let counter = 0
const delay = ms =>
new Promise(resolve => {
setTimeout(resolve, ms)
})
const fn = async (
ms, a, b
) => {
await delay(ms)
counter++
return a + b
}
const memoized = memoize(fn)
expect(await memoized(
100, 1, 2
)).toBe(3)
expect(await memoized(
100, 1, 2
)).toBe(3)
expect(await memoized(
100, 1, 2
)).toBe(3)
expect(counter).toBe(1)
expect(await memoized(
100, 2, 2
)).toBe(4)
expect(counter).toBe(2)
expect(await memoized(
100, 1, 2
)).toBe(3)
expect(counter).toBe(2)
})
test('string as argument', () => {
let count = 0
const foo = 'foo'
const tester = memoize(n => {
count++
return `${ n }bar`
})
tester(foo)
tester(foo)
tester(foo)
expect(tester(foo)).toEqual('foobar')
expect(count).toEqual(1)
tester('baz')
expect(tester('baz')).toEqual('bazbar')
expect(count).toEqual(2)
})
merge<Output>(target: object, newProps: object): Output
It creates a copy of target object with overidden newProps properties.
const target = { 'foo': 0, 'bar': 1 }
const newProps = { 'foo': 7 }
const result = R.merge(target, newProps)
// => { 'foo': 7, 'bar': 1 }
Try this R.merge example in Rambda REPL
export function merge(target, newProps){
if (arguments.length === 1) return _newProps => merge(target, _newProps)
return Object.assign(
{}, target || {}, newProps || {}
)
}
import { merge } from './merge'
const obj = {
foo : 1,
bar : 2,
}
test('happy', () => {
expect(merge(obj, { bar : 20 })).toEqual({
foo : 1,
bar : 20,
})
})
test('curry', () => {
expect(merge(obj)({ baz : 3 })).toEqual({
foo : 1,
bar : 2,
baz : 3,
})
})
/**
* https://github.com/selfrefactor/rambda/issues/77
*/
test('when undefined or null instead of object', () => {
expect(merge(null, undefined)).toEqual({})
expect(merge(obj, null)).toEqual(obj)
expect(merge(obj, undefined)).toEqual(obj)
expect(merge(undefined, obj)).toEqual(obj)
})
mergeAll<T>(list: object[]): T
It merges all objects of list array sequentially and returns the result.
const list = [
{a: 1},
{b: 2},
{c: 3}
]
const result = R.mergeAll(list)
const expected = {
a: 1,
b: 2,
c: 3
}
// => `result` is equal to `expected`
Try this R.mergeAll example in Rambda REPL
import { map } from './map'
import { merge } from './merge'
export function mergeAll(arr){
let willReturn = {}
map(val => {
willReturn = merge(willReturn, val)
}, arr)
return willReturn
}
import { mergeAll } from './mergeAll'
test('case 1', () => {
const arr = [ { a : 1 }, { b : 2 }, { c : 3 } ]
const expectedResult = {
a : 1,
b : 2,
c : 3,
}
expect(mergeAll(arr)).toEqual(expectedResult)
})
test('case 2', () => {
expect(mergeAll([ { foo : 1 }, { bar : 2 }, { baz : 3 } ])).toEqual({
foo : 1,
bar : 2,
baz : 3,
})
})
mergeDeepRight<Output>(target: object, newProps: object): Output
Creates a new object with the own properties of the first object merged with the own properties of the second object. If a key exists in both objects:
import { type } from './type'
export function mergeDeepRight(target, source){
if (arguments.length === 1){
return sourceHolder => mergeDeepRight(target, sourceHolder)
}
const willReturn = JSON.parse(JSON.stringify(target))
Object.keys(source).forEach(key => {
if (type(source[ key ]) === 'Object'){
if (type(target[ key ]) === 'Object'){
willReturn[ key ] = mergeDeepRight(target[ key ], source[ key ])
} else {
willReturn[ key ] = source[ key ]
}
} else {
willReturn[ key ] = source[ key ]
}
})
return willReturn
}
// import { mergeDeepRight } from 'ramda'
import { mergeDeepRight } from './mergeDeepRight'
const slave = {
name : 'evilMe',
age : 10,
contact : {
a : 1,
email : 'foo@example.com',
},
}
const master = {
age : 40,
contact : { email : 'baz@example.com' },
songs : { title : 'Remains the same' },
}
test('happy', () => {
const result = mergeDeepRight(slave, master)
const curryResult = mergeDeepRight(slave)(master)
const expected = {
age : 40,
name : 'evilMe',
contact : {
a : 1,
email : 'baz@example.com',
},
songs : { title : 'Remains the same' },
}
expect(result).toEqual(expected)
expect(curryResult).toEqual(expected)
})
test('ramda compatible test 1', () => {
const a = {
w : 1,
x : 2,
y : { z : 3 },
}
const b = {
a : 4,
b : 5,
c : { d : 6 },
}
const result = mergeDeepRight(a, b)
const expected = {
w : 1,
x : 2,
y : { z : 3 },
a : 4,
b : 5,
c : { d : 6 },
}
expect(result).toEqual(expected)
})
test('ramda compatible test 2', () => {
const a = {
a : {
b : 1,
c : 2,
},
y : 0,
}
const b = {
a : {
b : 3,
d : 4,
},
z : 0,
}
const result = mergeDeepRight(a, b)
const expected = {
a : {
b : 3,
c : 2,
d : 4,
},
y : 0,
z : 0,
}
expect(result).toEqual(expected)
})
test('ramda compatible test 3', () => {
const a = {
w : 1,
x : { y : 2 },
}
const result = mergeDeepRight(a, { x : { y : 3 } })
const expected = {
w : 1,
x : { y : 3 },
}
expect(result).toEqual(expected)
})
mergeLeft<Output>(newProps: object, target: object): Output
Same as R.merge, but in opposite direction.
const result = R.mergeLeft(
{a: 10},
{a: 1, b: 2}
)
// => {a:10, b: 2}
Try this R.mergeLeft example in Rambda REPL
import { merge } from './merge'
export function mergeLeft(x, y){
if (arguments.length === 1) return _y => mergeLeft(x, _y)
return merge(y, x)
}
import { mergeLeft } from './mergeLeft'
const obj = {
foo : 1,
bar : 2,
}
test('happy', () => {
expect(mergeLeft({ bar : 20 }, obj)).toEqual({
foo : 1,
bar : 20,
})
})
test('curry', () => {
expect(mergeLeft({ baz : 3 })(obj)).toEqual({
foo : 1,
bar : 2,
baz : 3,
})
})
test('when undefined or null instead of object', () => {
expect(mergeLeft(null, undefined)).toEqual({})
expect(mergeLeft(obj, null)).toEqual(obj)
expect(mergeLeft(obj, undefined)).toEqual(obj)
expect(mergeLeft(undefined, obj)).toEqual(obj)
})
min<T extends Ord>(x: T, y: T): T
It returns the lesser value between x and y.
const result = [
R.min(5, 7),
R.min('bar', 'foo'),
]
// => [5, 'bar']
Try this R.min example in Rambda REPL
export function min(x, y){
if (arguments.length === 1) return _y => min(x, _y)
return y < x ? y : x
}
import { min } from './min'
test('happy', () => {
expect(min(2, 1)).toBe(1)
expect(min(1)(2)).toBe(1)
})
minBy<T>(compareFn: (input: T) => Ord, x: T, y: T): T
It returns the lesser value between x and y according to compareFn function.
const compareFn = Math.abs
R.minBy(compareFn, -5, 2) // => -5
Try this R.minBy example in Rambda REPL
import { curry } from './curry'
export function minByFn(
compareFn, x, y
){
return compareFn(y) < compareFn(x) ? y : x
}
export const minBy = curry(minByFn)
import { minBy } from './minBy'
test('happy', () => {
expect(minBy(
Math.abs, -5, 2
)).toEqual(2)
})
test('curried', () => {
expect(minBy(Math.abs)(2, -5)).toEqual(2)
expect(minBy(Math.abs)(2)(-5)).toEqual(2)
})
Curried version of x%y.
R.modulo(17, 3) // => 2
Try this R.modulo example in Rambda REPL
move<T>(fromIndex: number, toIndex: number, list: T[]): T[]
It returns a copy of list with exchanged fromIndex and toIndex elements.
:boom: Rambda.move doesn't support negative indexes - it throws an error.
const list = [1, 2, 3]
const result = R.move(0, 1, list)
// => [2, 1, 3]
Try this R.move example in Rambda REPL
import { curry } from './curry'
function moveFn(
fromIndex, toIndex, list
){
if (fromIndex < 0 || toIndex < 0){
throw new Error('Rambda.move does not support negative indexes')
}
if (fromIndex > list.length - 1 || toIndex > list.length - 1) return list
const clone = list.slice()
clone[ fromIndex ] = list[ toIndex ]
clone[ toIndex ] = list[ fromIndex ]
return clone
}
export const move = curry(moveFn)
import { move } from './move'
const list = [ 1, 2, 3, 4 ]
test('happy', () => {
const result = move(
0, 1, list
)
expect(result).toEqual([ 2, 1, 3, 4 ])
})
test('with negative index', () => {
const errorMessage = 'Rambda.move does not support negative indexes'
expect(() => move(
0, -1, list
)).toThrowWithMessage(Error, errorMessage)
expect(() => move(
-1, 0, list
)).toThrowWithMessage(Error, errorMessage)
})
test('when indexes are outside the list outbounds', () => {
const result1 = move(
10, 1, list
)
const result2 = move(
1, 10, list
)
expect(result1).toEqual(list)
expect(result2).toEqual(list)
})
Curried version of x*y.
R.multiply(2, 4) // => 8
Try this R.multiply example in Rambda REPL
R.negate(420)// => -420
Try this R.negate example in Rambda REPL
nextIndex(index: number, list: any[]): number
It returns the next index of the list.
If we have reached the end of the list, then it will return 0.
const list = [1, 2, 3]
const result = [
R.nextIndex(0, list),
R.nextIndex(1, list),
R.nextIndex(2, list),
R.nextIndex(10, list)
]
// => [1, 2, 0, 0]
Try this R.nextIndex example in Rambda REPL
export function nextIndex(index, list){
return index >= list.length - 1 ? 0 : index + 1
}
import { nextIndex } from './nextIndex'
const list = [ 1, 2, 3, 4 ]
test('happy path', () => {
expect(nextIndex(2, list)).toEqual(3)
})
test('go back to the start', () => {
expect(nextIndex(3, list)).toEqual(0)
})
test('current index is too big', () => {
expect(nextIndex(32, list)).toEqual(0)
})
none<T>(predicate: (x: T) => boolean, list: T[]): boolean
It returns true, if all members of array list returns false, when applied as argument to predicate function.
const list = [ 0, 1, 2, 3, 4 ]
const predicate = x => x > 6
const result = R.none(predicate, arr)
// => true
Try this R.none example in Rambda REPL
export function none(predicate, list){
if (arguments.length === 1) return _list => none(predicate, _list)
for (let i = 0; i < list.length; i++){
if (!predicate(list[ i ])) return true
}
return false
}
import { none } from './none'
const isEven = n => n % 2 === 0
const isOdd = n => n % 2 === 1
const arr = [ 1, 3, 5, 7, 9, 11 ]
test('when true', () => {
expect(none(isEven, arr)).toBeTrue()
})
test('when false curried', () => {
expect(none(isOdd)(arr)).toBeFalse()
})
not(input: any): boolean
It returns a boolean negated version of input.
R.not(false) // true
Try this R.not example in Rambda REPL
export function not(input){
return !input
}
import { not } from './not'
test('not', () => {
expect(not(false)).toEqual(true)
expect(not(true)).toEqual(false)
expect(not(0)).toEqual(true)
expect(not(1)).toEqual(false)
})
nth<T>(index: number, list: T[]): T | undefined
Curried version of list[index].
const list = [1, 2, 3]
const str = 'foo'
const result = [
R.nth(2, list),
R.nth(6, list),
R.nth(0, str),
]
// => [3, undefined, 'f']
Try this R.nth example in Rambda REPL
export function nth(index, list){
if (arguments.length === 1) return _list => nth(index, _list)
const idx = index < 0 ? list.length + index : index
return Object.prototype.toString.call(list) === '[object String]' ?
list.charAt(idx) :
list[ idx ]
}
import { nth } from './nth'
test('happy', () => {
expect(nth(2, [ 1, 2, 3, 4 ])).toEqual(3)
})
test('with curry', () => {
expect(nth(2)([ 1, 2, 3, 4 ])).toEqual(3)
})
test('with string', () => {
expect(nth(2)('foo')).toEqual('o')
})
test('with negative index', () => {
expect(nth(-3)([ 1, 2, 3, 4 ])).toEqual(2)
})
It creates an object with a single key-value pair.
const result = R.objOf('foo', 'bar')
// => {foo: 'bar'}
Try this R.objOf example in Rambda REPL
of<T>(x: T): T[]
R.of(null); // => [null]
R.of([42]); // => [[42]]
Try this R.of example in Rambda REPL
export function of(value){
return [ value ]
}
import { of } from './of'
test('happy', () => {
expect(of(3)).toEqual([ 3 ])
expect(of(null)).toEqual([ null ])
})
ok(...inputs: any[]): (...schemas: any[]) => void | never
It checks if inputs are following schemas specifications according to R.isValid.
If validation fails, it throws.
:boom: It is same as
R.passbut instead of returningfalse, it throws an error.
const result = R.ok(
1,
['foo', 'bar']
)(
Number,
[String]
)
// => undefined
Try this R.ok example in Rambda REPL
import { any } from './any'
import { glue } from './glue'
import { fromPrototypeToString, isValid } from './isValid'
import { map } from './map'
import { type } from './type'
export function schemaToString(schema){
if (type(schema) !== 'Object'){
return fromPrototypeToString(schema).rule
}
return map(x => {
const { rule, parsed } = fromPrototypeToString(x)
const xType = type(x)
if (xType === 'Function' && !parsed) return 'Function'
return parsed ? rule : xType
}, schema)
}
export function check(singleInput, schema){
return isValid({
input : { singleInput },
schema : { singleInput : schema },
})
}
export function ok(...inputs){
return (...schemas) => {
let failedSchema
const anyError = any((singleInput, i) => {
const schema = schemas[ i ] === undefined ? schemas[ 0 ] : schemas[ i ]
const checked = check(singleInput, schema)
if (!checked){
failedSchema = JSON.stringify({
input : singleInput,
schema : schemaToString(schema),
})
}
return !checked
}, inputs)
if (anyError){
const errorMessage =
inputs.length > 1 ?
glue(`
Failed R.ok -
reason: ${ failedSchema }
all inputs: ${ JSON.stringify(inputs) }
all schemas: ${ JSON.stringify(schemas.map(schemaToString)) }
`,
'\n') :
`Failed R.ok - ${ failedSchema }`
throw new Error(errorMessage)
}
}
}
import { ok, schemaToString } from './ok'
test('happy', () => {
expect(() => {
ok(
1, 'foo', {}
)(
'number', 'string', 'object'
)
}).not.toThrow()
})
test('when validation fails', () => {
const errorMessage = `Failed R.ok -
reason: {"input":{},"schema":"string"}
all inputs: [1,"foo",{}]
all schemas: ["number","string","string"]`
expect(() =>
ok(
1, 'foo', {}
)(
'number', 'string', 'string'
)).toThrowWithMessage(Error, errorMessage)
})
/*
TODO
What about
{a: Function}
*/
test('schema in error message', () => {
const result = schemaToString({
_a : [ Number ],
a : Number,
b : x => x > 2,
c : [ 'foo', 'bar' ],
d : [ { a : String } ],
e : 'boolean',
f : Array,
h : Object,
})
expect(result).toMatchInlineSnapshot(`
Object {
"_a": "Array",
"a": "number",
"b": "Function",
"c": "Array",
"d": "Array",
"e": "String",
"f": "array",
"h": "object",
}
`)
})
test('error contains schema', () => {
try {
ok(
1, 'foo', {}
)(
{ a : Number }, String, String
)
expect(false).toBeTrue()
} catch (e){
expect(e.message.startsWith('Failed R.ok -')).toBeTruthy()
expect(e).toBeInstanceOf(Error)
}
})
test('when not throws with single schema', () => {
expect(() => ok(
1, 2, 3
)('number')).not.toThrow()
})
test('when throws with single schema', () => {
expect(() => ok(
1, 2, '3'
)('number')).toThrow()
})
test('when throws with single input', () => {
expect(() => ok('3')('number')).toThrow()
})
omit<T, K extends string>(propsToOmit: K[], obj: T): Omit<T, K>
It returns a partial copy of an obj without propsToOmit properties.
:boom: When using this method with
TypeScript, it is much easier to passpropsToOmitas an array. If passing a string, you will need to explicitly declare the output type.
const obj = {a: 1, b: 2, c: 3}
const propsToOmit = 'a,c,d'
const propsToOmitList = ['a', 'c', 'd']
const result = [
R.omit(propsToOmit, obj),
R.omit(propsToOmitList, obj)
]
// => [{b: 2}, {b: 2}]
Try this R.omit example in Rambda REPL
export function omit(propsToOmit, obj){
if (arguments.length === 1) return _obj => omit(propsToOmit, _obj)
if (obj === null || obj === undefined){
return undefined
}
const propsToOmitValue =
typeof propsToOmit === 'string' ? propsToOmit.split(',') : propsToOmit
const willReturn = {}
for (const key in obj){
if (!propsToOmitValue.includes(key)){
willReturn[ key ] = obj[ key ]
}
}
return willReturn
}
import { omit } from './omit'
test('with string as condition', () => {
const obj = {
a : 1,
b : 2,
c : 3,
}
const result = omit('a,c', obj)
const resultCurry = omit('a,c')(obj)
const expectedResult = { b : 2 }
expect(result).toEqual(expectedResult)
expect(resultCurry).toEqual(expectedResult)
})
test('with null', () => {
expect(omit('a,b', null)).toEqual(undefined)
})
test('doesn\'t work with number as property', () => {
expect(omit([ 42 ], {
a : 1,
42 : 2,
})).toEqual({
42 : 2,
a : 1,
})
})
test('happy', () => {
expect(omit([ 'a', 'c' ])({
a : 'foo',
b : 'bar',
c : 'baz',
})).toEqual({ b : 'bar' })
})
once<T extends (...args: any[]) => any>(func: T): T
It returns a function, which invokes only once fn function.
let result = 0
const addOnce = R.once((x) => result = result + x)
addOnce(1)
addOnce(1)
// => 1
Try this R.once example in Rambda REPL
import { curry } from './curry'
function onceFn(fn, context){
let result
return function (){
if (fn){
result = fn.apply(context || this, arguments)
fn = null
}
return result
}
}
export function once(fn, context){
if (arguments.length === 1){
const wrap = onceFn(fn, context)
return curry(wrap)
}
return onceFn(fn, context)
}
import { once } from './once'
test('with counter', () => {
let counter = 0
const runOnce = once(x => {
counter++
return x + 2
})
expect(runOnce(1)).toEqual(3)
runOnce(1)
runOnce(1)
runOnce(1)
expect(counter).toEqual(1)
})
test('happy path', () => {
const addOneOnce = once((
a, b, c
) => a + b + c, 1)
expect(addOneOnce(
10, 20, 30
)).toBe(60)
expect(addOneOnce(40)).toEqual(60)
})
or<T, U>(a: T, b: U): T | U
Logical OR
R.or(false, true); // => true
R.or(false, false); // => false
R.or(false, 'foo'); // => 'foo'
Try this R.or example in Rambda REPL
export function or(a, b){
if (arguments.length === 1) return _b => or(a, _b)
return a || b
}
import { or } from './or'
test('happy', () => {
expect(or(0, 'foo')).toBe('foo')
expect(or(true, true)).toBeTrue()
expect(or(false)(true)).toBeTrue()
expect(or(false, false)).toBeFalse()
})
over<T>(lens: Lens, fn: Arity1Fn, value: T): T
It returns a copied Object or Array with modified value received by applying function fn to lens focus.
const headLens = R.lensIndex(0)
R.over(headLens, R.toUpper, ['foo', 'bar', 'baz']) // => ['FOO', 'bar', 'baz']
Try this R.over example in Rambda REPL
import { curry } from './curry'
const Identity = x => ({
x,
map : fn => Identity(fn(x)),
})
function overFn(
lens, fn, object
){
return lens(x => Identity(fn(x)))(object).x
}
export const over = curry(overFn)
import { assoc } from './assoc'
import { lens } from './lens'
import { lensIndex } from './lensIndex'
import { lensPath } from './lensPath'
import { over } from './over'
import { prop } from './prop'
import { toUpper } from './toUpper'
const testObject = {
foo : 'bar',
baz : {
a : 'x',
b : 'y',
},
}
test('assoc lens', () => {
const assocLens = lens(prop('foo'), assoc('foo'))
const result = over(
assocLens, toUpper, testObject
)
const expected = {
...testObject,
foo : 'BAR',
}
expect(result).toEqual(expected)
})
test('path lens', () => {
const pathLens = lensPath('baz.a')
const result = over(
pathLens, toUpper, testObject
)
const expected = {
...testObject,
baz : {
a : 'X',
b : 'y',
},
}
expect(result).toEqual(expected)
})
test('index lens', () => {
const indexLens = lensIndex(0)
const result = over(indexLens, toUpper)([ 'foo', 'bar' ])
expect(result).toEqual([ 'FOO', 'bar' ])
})
partial<V0, V1, T>(fn: (x0: V0, x1: V1) => T, args: [V0]): (x1: V1) => T
It is very similar to R.curry, but you can pass initial arguments when you create the curried function.
R.partial will keep returning a function until all the arguments that the function fn expects are passed.
The name comes from the fact that you partially inject the inputs.
:boom: Rambda's partial doesn't need the input arguments to be wrapped as array.
const fn = (title, firstName, lastName) => {
return title + ' ' + firstName + ' ' + lastName + '!'
}
const canPassAnyNumberOfArguments = R.partial(fn, 'Hello')
const ramdaStyle = R.partial(fn, ['Hello'])
const finalFn = canPassAnyNumberOfArguments('Foo')
finalFn('Bar') // => 'Hello, Foo Bar!'
Try this R.partial example in Rambda REPL
export function partial(fn, ...args){
const len = fn.length
return (...rest) => {
if (args.length + rest.length >= len){
return fn(...args, ...rest)
}
return partial(fn, ...[ ...args, ...rest ])
}
}
import { partial } from './partial'
import { type } from './type'
const greet = (
salutation, title, firstName, lastName
) =>
salutation + ', ' + title + ' ' + firstName + ' ' + lastName + '!'
test('happy', () => {
const canPassAnyNumberOfArguments = partial(
greet, 'Hello', 'Ms.'
)
const fn = canPassAnyNumberOfArguments('foo')
const sayHello = partial(greet, [ 'Hello' ])
const sayHelloRamda = partial(sayHello, [ 'Ms.' ])
expect(type(fn)).toBe('Function')
expect(fn('bar')).toBe('Hello, Ms. foo bar!')
expect(sayHelloRamda('foo', 'bar')).toBe('Hello, Ms. foo bar!')
})
test('extra arguments are ignored', () => {
const canPassAnyNumberOfArguments = partial(
greet, 'Hello', 'Ms.'
)
const fn = canPassAnyNumberOfArguments('foo')
expect(type(fn)).toBe('Function')
expect(fn(
'bar', 1, 2
)).toBe('Hello, Ms. foo bar!')
})
test('when array is input', () => {
const fooFn = (
a, b, c, d
) => ({
a,
b,
c,
d,
})
const barFn = partial(
fooFn, [ 1, 2 ], []
)
expect(barFn(1, 2)).toEqual({
a : [ 1, 2 ],
b : [],
c : 1,
d : 2,
})
})
test('ramda spec', () => {
const sayHello = partial(greet, 'Hello')
const sayHelloToMs = partial(sayHello, 'Ms.')
expect(sayHelloToMs('Jane', 'Jones')).toBe('Hello, Ms. Jane Jones!')
})
partialCurry<Input, PartialInput, Output>(
fn: (input: Input) => Output,
partialInput: PartialInput,
): (input: Pick<Input, Exclude<keyof Input, keyof PartialInput>>) => Output
R.partialCurry is a curry helper designed specifically for functions accepting object as a single argument.
Initially the function knows only a part from the whole input object and then R.partialCurry helps in preparing the function for the second part, when it receives the rest of the input.
:boom: Curried function can be asynchronous
const fn = ({ a, b, c }) => a + b + c
const curried = partialCurry(fn, { a : 1 })
const result = curried({
b : 2,
c : 3,
})
// => 6
Try this R.partialCurry example in Rambda REPL
import { merge } from './merge'
import { type } from './type'
export function partialCurry(fn, input){
return rest => {
if (type(fn) === 'Async'){
return new Promise((resolve, reject) => {
fn(merge(rest, input)).then(resolve)
.catch(reject)
})
}
return fn(merge(rest, input))
}
}
import { delay } from './delay'
import { partialCurry } from './partialCurry'
import { type } from './type'
test('with plain function', () => {
const fn = ({ a, b, c }) => a + b + c
const curried = partialCurry(fn, { a : 1 })
expect(type(curried)).toEqual('Function')
expect(curried({
b : 2,
c : 3,
})).toEqual(6)
})
test('with function that throws an error', () => {
const fn = ({ a, b, c }) => {
throw new Error('foo')
}
const curried = partialCurry(fn, { a : 1 })
expect(type(curried)).toEqual('Function')
expect(() =>
curried({
b : 2,
c : 3,
})).toThrowWithMessage(Error, 'foo')
})
test('with async', async () => {
const fn = async ({ a, b, c }) => {
await delay(100)
return a + b + c
}
const curried = partialCurry(fn, { a : 1 })
const result = await curried({
b : 2,
c : 3,
})
expect(result).toEqual(6)
})
test('async function throwing an error', async () => {
const fn = async ({ a, b, c }) => {
await delay(100)
throw new Error('foo')
}
const curried = partialCurry(fn, { a : 1 })
try {
await curried({
b : 2,
c : 3,
})
expect(true).toBeFalsy()
} catch (e){
expect(e.message).toBe('foo')
}
})
partition<T>(
predicate: Predicate<T>,
input: T[]
): [T[], T[]]
It will return array of two objects/arrays according to predicate function. The first member holds all instances of input that pass the predicate function, while the second member - those who doesn't.
const list = [1, 2, 3]
const obj = {a: 1, b: 2, c: 3}
const predicate = x => x > 2
const result = [
R.partition(predicate, list),
R.partition(predicate, obj)
]
const expected = [
[[3], [1, 2]],
[{c: 3}, {a: 1, b: 2}],
]
// `result` is equal to `expected`
Try this R.partition example in Rambda REPL
import { _isArray } from './_internals/_isArray'
export function partitionObject(predicate, iterable){
const yes = {}
const no = {}
Object.entries(iterable).forEach(([ prop, value ]) => {
if (predicate(value, prop)){
yes[ prop ] = value
} else {
no[ prop ] = value
}
})
return [ yes, no ]
}
export function partitionArray(predicate, list, indexed = false){
const yes = []
const no = []
let counter = -1
while (counter++ < list.length - 1){
if (indexed ? predicate(list[ counter ], counter) : predicate(list[ counter ])){
yes.push(list[ counter ])
} else {
no.push(list[ counter ])
}
}
return [ yes, no ]
}
export function partition(predicate, iterable){
if (arguments.length === 1){
return listHolder => partition(predicate, listHolder)
}
if (!_isArray(iterable)) return partitionObject(predicate, iterable)
return partitionArray(predicate, iterable)
}
import { partition } from './partition'
test('with array', () => {
const predicate = x => x > 2
const list = [ 1, 2, 3, 4 ]
const result = partition(predicate, list)
const expectedResult = [
[ 3, 4 ],
[ 1, 2 ],
]
expect(result).toEqual(expectedResult)
})
test('with object', () => {
const predicate = (value, prop) => {
expect(typeof prop).toBe('string')
return value > 2
}
const hash = {
a : 1,
b : 2,
c : 3,
d : 4,
}
const result = partition(predicate)(hash)
const expectedResult = [
{
c : 3,
d : 4,
},
{
a : 1,
b : 2,
},
]
expect(result).toEqual(expectedResult)
})
test('readme example', () => {
const list = [ 1, 2, 3 ]
const obj = {
a : 1,
b : 2,
c : 3,
}
const predicate = x => x > 2
const result = [ partition(predicate, list), partition(predicate, obj) ]
const expected = [
[ [ 3 ], [ 1, 2 ] ],
[
{ c : 3 },
{
a : 1,
b : 2,
},
],
]
expect(result).toEqual(expected)
})
partitionIndexed<T>(
predicate: IndexedPredicate<T>,
input: T[]
): [T[], T[]]
import { partitionObject, partitionArray } from './partition'
import { _isArray } from './_internals/_isArray'
export function partitionIndexed(predicate, iterable){
if (arguments.length === 1){
return listHolder => partitionIndexed(predicate, listHolder)
}
if (!_isArray(iterable)) return partitionObject(predicate, iterable)
return partitionArray(predicate, iterable, true)
}
import { partitionIndexed } from './partitionIndexed'
test('with array', () => {
const predicate = (x, i) => {
expect(x).toBeNumber()
return x > 2
}
const list = [ 1, 2, 3, 4 ]
const result = partitionIndexed(predicate, list)
const curried = partitionIndexed(predicate)(list)
const expectedResult = [
[ 3, 4 ],
[ 1, 2 ],
]
expect(result).toEqual(expectedResult)
expect(curried).toEqual(expectedResult)
})
pass(...inputs: any[]): (...rules: any[]) => boolean
It checks if inputs are following schemas specifications according to R.isValid.
const result = R.pass(
1,
['foo','bar']
)(
Number,
[String]
)
// => true
Try this R.pass example in Rambda REPL
import { any } from './any'
import { check } from './ok'
export function pass(...inputs){
return (...schemas) =>
any((x, i) => {
const schema = schemas[ i ] === undefined ? schemas[ 0 ] : schemas[ i ]
return !check(x, schema)
}, inputs) === false
}
import { pass } from './pass'
test('true on success', () => {
const result = pass(
1, 'foo', {}
)(
'number', 'string', 'object'
)
expect(result).toBeTrue()
})
test('false on failure', () => {
expect(pass(
1, 'foo', {}
)(
'number', 'string', 'string'
)).toBeFalse()
})
test('true when single schema', () => {
expect(pass(
1, 2, 3
)('number')).toBeTrue()
})
test('false when single schema', () => {
expect(pass(
1, 'foo', {}
)('number')).toBeFalse()
})
test('array of schemas', () => {
const result = pass([ { a : 1 }, { a : 2 }, { a : 3 } ])([ { a : Number } ])
expect(result).toBeTruthy()
})
test('reame example', () => {
const result = pass(1, [ 'foo', 'bar' ])(Number, [ String ])
expect(result).toBeTruthy()
})
path<Input, T>(pathToSearch: Path, obj: Input): T | undefined
If pathToSearch is 'a.b' then it will return 1 if obj is {a:{b:1}}.
It will return undefined, if such path is not found.
:boom: String anotation of
pathToSearchis one of the differences betweenRambdaandRamda.
const obj = {a: {b: 1}}
const pathToSearch = 'a.b'
const pathToSearchList = ['a', 'b']
const result = [
R.path(pathToSearch, obj),
R.path(pathToSearchList, obj),
R.path('a.b.c.d', obj)
]
// => [1, 1, undefined]
Try this R.path example in Rambda REPL
export function path(pathInput, obj){
if (arguments.length === 1) return _obj => path(pathInput, _obj)
if (obj === null || obj === undefined){
return undefined
}
let willReturn = obj
let counter = 0
const pathArrValue =
typeof pathInput === 'string' ? pathInput.split('.') : pathInput
while (counter < pathArrValue.length){
if (willReturn === null || willReturn === undefined){
return undefined
}
if(willReturn[ pathArrValue[ counter ] ] === null) return undefined
willReturn = willReturn[ pathArrValue[ counter ] ]
counter++
}
return willReturn
}
import { path } from './path'
test('with array inside object', () => {
const obj = { a : { b : [ 1, { c : 1 } ] } }
expect(path('a.b.1.c', obj)).toBe(1)
})
test('works with undefined', () => {
const obj = { a : { b : { c : 1 } } }
expect(path('a.b.c.d.f', obj)).toBeUndefined()
expect(path('foo.babaz', undefined)).toBeUndefined()
expect(path('foo.babaz')(undefined)).toBeUndefined()
})
test('works with string instead of array', () => {
expect(path('foo.bar.baz')({ foo : { bar : { baz : 'yes' } } })).toEqual('yes')
})
test('path', () => {
expect(path([ 'foo', 'bar', 'baz' ])({ foo : { bar : { baz : 'yes' } } })).toEqual('yes')
expect(path([ 'foo', 'bar', 'baz' ])(null)).toBeUndefined()
expect(path([ 'foo', 'bar', 'baz' ])({ foo : { bar : 'baz' } })).toBeUndefined()
})
test("null is not a valid path", () => {
expect(
path('audio_tracks', {a: 1, audio_tracks: null})
).toBeUndefined()
})
pathEq(pathToSearch: Path, target: any, input: any): boolean
It returns true if pathToSearch of input object is equal to target value.
pathToSearch is passed to R.path, which means that it can be either a string or an array. Also equality between target and the found value is determined by R.equals.
const path = 'a.b'
const target = {c: 1}
const input = {a: {b: {c: 1}}}
const result = R.pathEq(
path,
target,
input
)
// => true
Try this R.pathEq example in Rambda REPL
import { curry } from './curry'
import { equals } from './equals'
import { path } from './path'
function pathEqFn(
pathToSearch, target, input
){
return equals(path(pathToSearch, input), target)
}
export const pathEq = curry(pathEqFn)
import { pathEq } from './pathEq'
test('when true', () => {
const path = 'a.b'
const obj = { a : { b : { c : 1 } } }
const target = { c : 1 }
expect(pathEq(
path, target, obj
)).toBeTrue()
})
test('when false', () => {
const path = 'a.b'
const obj = { a : { b : 1 } }
const target = 2
expect(pathEq(path, target)(obj)).toBeFalse()
})
test('when wrong path', () => {
const path = 'foo.bar'
const obj = { a : { b : 1 } }
const target = 2
expect(pathEq(
path, target, obj
)).toBeFalse()
})
pathOr<T>(defaultValue: T, pathToSearch: Path, obj: any): T
It reads obj input and returns either R.path(pathToSearch, obj) result or defaultValue input.
const defaultValue = 'DEFAULT_VALUE'
const pathToSearch = 'a.b'
const pathToSearchList = ['a', 'b']
const obj = {
a : {
b : 1
}
}
const result = [
R.pathOr(DEFAULT_VALUE, pathToSearch, obj)
R.pathOr(DEFAULT_VALUE, pathToSearchList, obj)
R.pathOr(DEFAULT_VALUE, 'a.b.c', obj)
]
// => [1, 1, 'DEFAULT_VALUE']
Try this R.pathOr example in Rambda REPL
import { curry } from './curry'
import { defaultTo } from './defaultTo'
import { path } from './path'
function pathOrFn(
defaultValue, list, obj
){
return defaultTo(defaultValue, path(list, obj))
}
export const pathOr = curry(pathOrFn)
import { pathOr } from './pathOr'
test('with undefined', () => {
const result = pathOr(
'foo', 'x.y', { x : { y : 1 } }
)
expect(result).toEqual(1)
})
test('with null', () => {
const result = pathOr(
'foo', 'x.y', null
)
expect(result).toEqual('foo')
})
test('with NaN', () => {
const result = pathOr(
'foo', 'x.y', NaN
)
expect(result).toEqual('foo')
})
test('curry case (x)(y)(z)', () => {
const result = pathOr('foo')('x.y.z')({ x : { y : { a : 1 } } })
expect(result).toEqual('foo')
})
test('curry case (x)(y,z)', () => {
const result = pathOr('foo', 'x.y.z')({ x : { y : { a : 1 } } })
expect(result).toEqual('foo')
})
test('curry case (x,y)(z)', () => {
const result = pathOr('foo')('x.y.z', { x : { y : { a : 1 } } })
expect(result).toEqual('foo')
})
paths<Input, T>(pathsToSearch: Path[], obj: Input): (T | undefined)[]
It loops over members of pathsToSearch as singlePath and returns the array produced by R.path(singlePath, obj).
Because it calls R.path, then singlePath can be either string or a list.
const obj = {
a : {
b : {
c : 1,
d : 2
}
}
}
const result = R.paths([
'a.b.c',
'a.b.c.d',
'a.b.c.d.e',
], obj)
// => [1, 2, undefined]
Try this R.paths example in Rambda REPL
import { path } from './path'
export function paths(pathsToSearch, obj){
if (arguments.length === 1){
return _obj => paths(pathsToSearch, _obj)
}
return pathsToSearch.map(singlePath => path(singlePath, obj))
}
import { paths } from './paths'
const obj = {
a : {
b : {
c : 1,
d : 2,
},
},
p : [ { q : 3 } ],
x : {
y : 'FOO',
z : [ [ {} ] ],
},
}
test('with string path + curry', () => {
const pathsInput = [ 'a.b.d', 'p.q' ]
const expected = [ 2, undefined ]
const result = paths(pathsInput, obj)
const curriedResult = paths(pathsInput)(obj)
expect(result).toEqual(expected)
expect(curriedResult).toEqual(expected)
})
test('with array path', () => {
const result = paths([
[ 'a', 'b', 'c' ],
[ 'x', 'y' ],
],
obj)
expect(result).toEqual([ 1, 'FOO' ])
})
test('takes a paths that contains indices into arrays', () => {
expect(paths([
[ 'p', 0, 'q' ],
[ 'x', 'z', 0, 0 ],
],
obj)).toEqual([ 3, {} ])
expect(paths([
[ 'p', 0, 'q' ],
[ 'x', 'z', 2, 1 ],
],
obj)).toEqual([ 3, undefined ])
})
test('gets a deep property\'s value from objects', () => {
expect(paths([ [ 'a', 'b' ] ], obj)).toEqual([ obj.a.b ])
expect(paths([ [ 'p', 0 ] ], obj)).toEqual([ obj.p[ 0 ] ])
})
test('returns undefined for items not found', () => {
expect(paths([ [ 'a', 'x', 'y' ] ], obj)).toEqual([ undefined ])
expect(paths([ [ 'p', 2 ] ], obj)).toEqual([ undefined ])
})
pick<T, K extends string | number | symbol>(propsToPick: K[], input: T): Pick<T, Exclude<keyof T, Exclude<keyof T, K>>>
It returns a partial copy of an input containing only propsToPick properties.
input can be either an object or an array.
String anotation of propsToPick is one of the differences between Rambda and Ramda.
:boom: When using this method with
TypeScript, it is much easier to passpropsToPickas an array. If passing a string, you will need to explicitly declare the output type.
const obj = {
a : 1,
b : false,
foo: 'cherry'
}
const list = [1, 2, 3, 4]
const propsToPick = 'a,foo'
const propsToPickList = ['a', 'foo']
const result = [
R.pick(propsToPick, obj),
R.pick(propsToPickList, obj),
R.pick('a,bar', obj),
R.pick('bar', obj),
R.pick([0, 3], list),
R.pick('0,3', list),
]
const expected = [
{a:1, foo: 'cherry'},
{a:1, foo: 'cherry'},
{a:1},
{},
[1,4],
[1,4]
]
// => `result` is equal to `expected`
Try this R.pick example in Rambda REPL
export function pick(propsToPick, input){
if (arguments.length === 1) return _input => pick(propsToPick, _input)
if (input === null || input === undefined){
return undefined
}
const keys =
typeof propsToPick === 'string' ? propsToPick.split(',') : propsToPick
const willReturn = {}
let counter = 0
while (counter < keys.length){
if (keys[ counter ] in input){
willReturn[ keys[ counter ] ] = input[ keys[ counter ] ]
}
counter++
}
return willReturn
}
import { pick } from './pick'
const obj = {
a : 1,
b : 2,
c : 3,
}
test('props to pick is a string', () => {
const result = pick('a,c', obj)
const resultCurry = pick('a,c')(obj)
const expectedResult = {
a : 1,
c : 3,
}
expect(result).toEqual(expectedResult)
expect(resultCurry).toEqual(expectedResult)
})
test('when prop is missing', () => {
const result = pick('a,d,f', obj)
expect(result).toEqual({ a : 1 })
})
test('props to pick is an array', () => {
expect(pick([ 'a', 'c' ])({
a : 'foo',
b : 'bar',
c : 'baz',
})).toEqual({
a : 'foo',
c : 'baz',
})
expect(pick([ 'a', 'd', 'e', 'f' ])({
a : 'foo',
b : 'bar',
c : 'baz',
})).toEqual({ a : 'foo' })
expect(pick('a,d,e,f')(null)).toEqual(undefined)
})
test('works with list as input and number as props - props to pick is an array', () => {
const result = pick([ 1, 2 ], [ 'a', 'b', 'c', 'd' ])
expect(result).toEqual({
1 : 'b',
2 : 'c',
})
})
test('works with list as input and number as props - props to pick is a string', () => {
const result = pick('1,2', [ 'a', 'b', 'c', 'd' ])
expect(result).toEqual({
1 : 'b',
2 : 'c',
})
})
test('with symbol', () => {
const symbolProp = Symbol('s')
expect(pick([ symbolProp ], { [ symbolProp ] : 'a' })).toMatchInlineSnapshot(`
Object {
Symbol(s): "a",
}
`)
})
pickAll<T, U>(propsToPick: string[], input: T): U
Same as R.pick but it won't skip the missing props, i.e. it will assign them to undefined.
:boom: When using this method with
TypeScript, it is much easier to passpropsToPickas an array. If passing a string, you will need to explicitly declare the output type.
const obj = {
a : 1,
b : false,
foo: 'cherry'
}
const propsToPick = 'a,foo,bar'
const propsToPickList = ['a', 'foo', 'bar']
const result = [
R.pickAll(propsToPick, obj),
R.pickAll(propsToPickList, obj),
R.pickAll('a,bar', obj),
R.pickAll('bar', obj),
]
const expected = [
{a:1, foo: 'cherry', bar: undefined},
{a:1, foo: 'cherry', bar: undefined},
{a:1, bar: undefined},
{bar: undefined}
]
// => `result` is equal to `expected`
Try this R.pickAll example in Rambda REPL
export function pickAll(propsToPick, obj){
if (arguments.length === 1) return _obj => pickAll(propsToPick, _obj)
if (obj === null || obj === undefined){
return undefined
}
const keysValue =
typeof propsToPick === 'string' ? propsToPick.split(',') : propsToPick
const willReturn = {}
let counter = 0
while (counter < keysValue.length){
if (keysValue[ counter ] in obj){
willReturn[ keysValue[ counter ] ] = obj[ keysValue[ counter ] ]
} else {
willReturn[ keysValue[ counter ] ] = undefined
}
counter++
}
return willReturn
}
import { pickAll } from './pickAll'
test('when input is undefined or null', () => {
expect(pickAll('a', null)).toBe(undefined)
expect(pickAll('a', undefined)).toBe(undefined)
})
test('with string as condition', () => {
const obj = {
a : 1,
b : 2,
c : 3,
}
const result = pickAll('a,c', obj)
const resultCurry = pickAll('a,c')(obj)
const expectedResult = {
a : 1,
b : undefined,
c : 3,
}
expect(result).toEqual(expectedResult)
expect(resultCurry).toEqual(expectedResult)
})
test('with array as condition', () => {
expect(pickAll([ 'a', 'b', 'c' ], {
a : 'foo',
c : 'baz',
})).toEqual({
a : 'foo',
b : undefined,
c : 'baz',
})
})
It performs left-to-right function composition.
const result = R.pipe(
R.filter(val => val > 2),
R.map(a => a * 2)
)([1, 2, 3, 4])
// => [6, 8]
Try this R.pipe example in Rambda REPL
pipeAsync<Out>(
...fns: (Async<any> | Func<any>)[]
): (input: any) => Promise<Out>
Asynchronous version of R.pipe
:boom: It doesn't work with promises or function returning promises such as
const foo = input => new Promise(...).
const add = async x => {
await R.delay(100)
return x + 1
}
const multiply = async x => {
await R.delay(100)
return x * 2
}
const result = await R.pipeAsync(
add,
multiply
)(1)
// `result` resolves to `4`
Try this R.pipeAsync example in Rambda REPL
import { type } from './type'
export function pipeAsync(...inputArguments){
return async function (startArgument){
let argumentsToPass = startArgument
while (inputArguments.length !== 0){
const fn = inputArguments.shift()
const typeFn = type(fn)
if (typeFn === 'Async'){
argumentsToPass = await fn(argumentsToPass)
} else {
argumentsToPass = fn(argumentsToPass)
if (type(argumentsToPass) === 'Promise'){
argumentsToPass = await argumentsToPass
}
}
}
return argumentsToPass
}
}
import { delay } from './delay'
import { equals } from './equals'
import { map } from './map'
import { pipeAsync } from './pipeAsync'
async function identity(x){
await delay(100)
return x
}
test('happy', async () => {
const fn1 = async x => {
await delay(100)
return x.map(xx => xx + 1)
}
const fn2 = async x => {
await delay(100)
return x.map(xx => xx * 2)
}
const result = await pipeAsync(fn1,
fn2)(await Promise.all([ identity(1), identity(2), identity(3) ]))
expect(result).toEqual([ 4, 6, 8 ])
})
const delayFn = ms =>
new Promise(resolve => {
resolve(ms + 1)
})
test('with function returning promise', async () => {
const result = await pipeAsync(
x => x,
x => x + 1,
delayFn,
x => x
)(1)
expect(result).toEqual(3)
})
test('throw error', async () => {
const fn = async () => {
await delay(1)
JSON.parse('{foo')
}
let didThrow = false
try {
await pipeAsync(x => x, fn)(20)
} catch (e){
didThrow = true
}
expect(didThrow).toBeTrue()
})
piped<A, B>(input: A, fn0: (x: A) => B) : B
It is basically R.pipe, but instead of passing input argument as R.pipe(...)(input), you pass it as the first argument.
:boom: Independently, similar method is implemented in
Ramadalibrary, but there the name of the method ispipe- Remeda.pipe
const result = piped(
[1, 2, 3],
R.filter(x => x > 1),
R.map(x => x*10),
)
// => [20, 30]
Try this R.piped example in Rambda REPL
import { pipe } from './pipe'
export function piped(...inputs){
const [ input, ...fnList ] = inputs
return pipe(...fnList)(input)
}
import { add } from './add'
import { filter } from './filter'
import { map } from './map'
import { piped } from './piped'
test('happy', () => {
const result = piped(
[ 1, 2, 3 ],
filter(x => x > 1),
map(x => x * 10),
map(add(1))
)
const expectedResult = [ 21, 31 ]
expect(result).toEqual(expectedResult)
})
pipedAsync<T>(
input: any,
...fns: (Func<any> | Async<any>)[]
): Promise<T>
It accepts input as first argument and series of functions as next arguments. It is same as R.pipe but with support for asynchronous functions.
:boom: Functions that return
Promisewill be handled as regular function not asynchronous. Such example isconst foo = input => new Promise(...).
const result = R.pipedAsync(
100,
async x => {
await R.delay(100)
return x + 2
},
R.add(2),
async x => {
const delayed = await R.delay(100)
return delayed + x
}
)
const expected = 'RAMBDAX_DELAY104'
// `result` resolves to `expected`
Try this R.pipedAsync example in Rambda REPL
import { type } from './type'
export async function pipedAsync(...inputs){
const [ input, ...fnList ] = inputs
let argumentsToPass = input
while (fnList.length !== 0){
const fn = fnList.shift()
const typeFn = type(fn)
if (typeFn === 'Async'){
argumentsToPass = await fn(argumentsToPass)
} else {
argumentsToPass = fn(argumentsToPass)
}
}
return argumentsToPass
}
import { add } from './add'
import { delay } from './delay'
import { pipedAsync } from './pipedAsync'
const fn1 = async x => {
await delay(100)
return x + 2
}
const fn2 = async x => {
await delay(100)
return x + 3
}
test('happy', async () => {
const result = await pipedAsync(
1, fn1, add(2), fn2
)
expect(result).toBe(8)
})
pluck<K extends keyof T, T>(property: K, list: T[]): T[K][]
It returns list of the values of property taken from the all objects inside list.
const list = [{a: 1}, {a: 2}, {b: 3}]
const property = 'a'
R.pluck(property, list)
// => [1, 2]
Try this R.pluck example in Rambda REPL
import { map } from './map'
export function pluck(property, list){
if (arguments.length === 1) return _list => pluck(property, _list)
const willReturn = []
map(x => {
if (x[ property ] !== undefined){
willReturn.push(x[ property ])
}
}, list)
return willReturn
}
import { pluck } from './pluck'
test('happy', () => {
expect(pluck('a')([ { a : 1 }, { a : 2 }, { b : 1 } ])).toEqual([ 1, 2 ])
})
test('with number', () => {
const input = [
[ 1, 2 ],
[ 3, 4 ],
]
expect(pluck(0, input)).toEqual([ 1, 3 ])
})
prepend<T>(x: T, input: T[]): T[]
It adds element x at the beginning of list.
const result = R.prepend('foo', ['bar', 'baz'])
// => ['foo', 'bar', 'baz']
Try this R.prepend example in Rambda REPL
export function prepend(x, input){
if (arguments.length === 1) return _input => prepend(x, _input)
if (typeof input === 'string') return [ x ].concat(input.split(''))
return [ x ].concat(input)
}
import { prepend } from './prepend'
test('happy', () => {
expect(prepend('yes', [ 'foo', 'bar', 'baz' ])).toEqual([
'yes',
'foo',
'bar',
'baz',
])
})
test('with empty list', () => {
expect(prepend('foo')([])).toEqual([ 'foo' ])
})
test('with string instead of array', () => {
expect(prepend('foo')('bar')).toEqual([ 'foo', 'b', 'a', 'r' ])
})
prevIndex(index: number, list: any[]): number
It returns the next index of the list when the order is descending.
If we have reached the beginning of the list, then it will return the last index of the list.
:boom: Unlike
R.nextIndex, which safeguards against index out of bounds, this method does not.
const list = [1, 2, 3]
const result = [
R.prevIndex(0, list),
R.prevIndex(1, list),
R.prevIndex(2, list),
]
// => [2, 0, 1]
Try this R.prevIndex example in Rambda REPL
export function prevIndex(index, list){
return index === 0 ? list.length - 1 : index - 1
}
import { prevIndex } from './prevIndex'
const list = [ 1, 2, 3, 4 ]
test('happy path 1', () => {
expect(prevIndex(2, list)).toEqual(1)
})
test('happy path 2', () => {
expect(prevIndex(0, list)).toEqual(3)
})
produce<Input extends any, Output>(
rules: ProduceRules<Output, keyof Output, Input>,
input: Input
): Output
It returns an object created by applying each value of rules to input argument.
:boom: In Typescript context,
rulesfunctions can be only 1 level deep. In Javascript context, there is no such restriction.
const rules = {
foo: R.pipe(R.add(1), R.add(2)),
a: {b: add(3)}
}
const input = i
const result = R.produce(rules, input)
const expected = {
foo: 4,
a: {b: 4}
}
// => `result` is equal to `expected`
Try this R.produce example in Rambda REPL
import { map } from './map'
import { type } from './type'
export function produce(rules, input){
if (arguments.length === 1){
return _input => produce(rules, _input)
}
return map(singleRule =>
type(singleRule) === 'Object' ?
produce(singleRule, input) :
singleRule(input),
rules)
}
import { add, pipe } from '../rambda'
import { produce } from './produce'
const rules = {
a : pipe(add(2), add(3)),
b : x => ({ foo : x }),
c : {
d : add(2),
e : add(10),
},
}
const expected = {
a : 6,
b : { foo : 1 },
c : {
d : 3,
e : 11,
},
}
test('happy', () => {
const result = produce(rules, 1)
expect(result).toEqual(expected)
})
test('curried', () => {
const result = produce(rules)(1)
expect(result).toEqual(expected)
})
produceAsync<Input extends any, Output>(
rules: ProduceAsyncRules<Output, keyof Output, Input>,
input: Input
): Promise<Output>
It returns an object created by applying each value of rules to input argument.
rules input is an object with synchronous or asynchronous functions as values.
The return value is wrapped in a promise, even if all rules are synchronous functions.
const rules = {
foo: async x => {
await R.delay(100)
return x > 1
},
bar: x => ({baz: x})
}
const input = 2
const result = await R.produceAsync(rules, input)
const expected = {
foo: true,
bar: {baz: 2}
}
// => `result` is equal to `expected`
Try this R.produceAsync example in Rambda REPL
import { map } from './map'
import { type } from './type'
function promisify({ condition, input, prop }){
return new Promise((resolve, reject) => {
if (type(condition) !== 'Async'){
return resolve({
type : prop,
payload : condition(input),
})
}
condition(input)
.then(result => {
resolve({
type : prop,
payload : result,
})
})
.catch(err => reject(err))
})
}
function produceFn(conditions, input){
let asyncConditionsFlag = false
for (const prop in conditions){
if (
asyncConditionsFlag === false &&
type(conditions[ prop ]) === 'Async'
){
asyncConditionsFlag = true
}
}
if (asyncConditionsFlag === false){
const willReturn = {}
for (const prop in conditions){
willReturn[ prop ] = conditions[ prop ](input)
}
return Promise.resolve(willReturn)
}
const promised = []
for (const prop in conditions){
const condition = conditions[ prop ]
promised.push(promisify({
input,
condition,
prop,
}))
}
return new Promise((resolve, reject) => {
Promise.all(promised)
.then(results => {
const willReturn = {}
map(result => willReturn[ result.type ] = result.payload, results)
resolve(willReturn)
})
.catch(err => reject(err))
})
}
export function produceAsync(conditions, input){
if (arguments.length === 1){
return async _input => produceFn(conditions, _input)
}
return new Promise((resolve, reject) => {
produceFn(conditions, input).then(resolve)
.catch(reject)
})
}
import { delay } from './delay'
import { produceAsync } from './produceAsync'
test('happy', async () => {
const result = await produceAsync({
foo : async x => {
await delay(100)
return `${ x }_ZEPPELIN`
},
bar : x => x.length === 3,
},
'LED')
const expected = {
foo : 'LED_ZEPPELIN',
bar : true,
}
expect(result).toEqual(expected)
})
test('when all rules are synchronous', async () => {
const result = await produceAsync({
foo : x => `${ x }_ZEPPELIN`,
bar : x => x.length === 3,
},
'LED')
const expected = {
foo : 'LED_ZEPPELIN',
bar : true,
}
expect(result).toEqual(expected)
})
test('with error', async () => {
const fn = produceAsync({
foo : async x => {
await delay(100)
throw new Error(`${ x }_ZEPPELIN`)
},
bar : inputArgument => inputArgument === 5,
})
await expect(fn('LED')).rejects.toThrow('LED_ZEPPELIN')
})
product(list: number[]): number
R.product([ 2, 3, 4 ])
// => 24)
Try this R.product example in Rambda REPL
import { multiply } from './multiply'
import { reduce } from './reduce'
export const product = reduce(multiply, 1)
import { product } from './product'
test('happy', () => {
expect(product([ 2, 3, 4 ])).toEqual(24)
})
test('bad input', () => {
expect(product([ null ])).toEqual(0)
expect(product([])).toEqual(1)
})
prop<P extends keyof T, T>(propToFind: P, obj: T): T[P]
It returns the value of property propToFind in obj.
If there is no such property, it returns undefined.
const result = [
R.prop('x', {x: 100}),
R.prop('x', {a: 1})
]
// => [100, undefined]
Try this R.prop example in Rambda REPL
export function prop(propToFind, obj){
if (arguments.length === 1) return _obj => prop(propToFind, _obj)
if (!obj) return undefined
return obj[ propToFind ]
}
import { prop } from './prop'
test('prop', () => {
expect(prop('foo')({ foo : 'baz' })).toEqual('baz')
expect(prop('bar')({ foo : 'baz' })).toEqual(undefined)
expect(prop('bar')(null)).toEqual(undefined)
})
propEq<K extends string | number>(propToFind: K, valueToMatch: any, obj: Record<K, any>): boolean
It returns true if obj has property propToFind and its value is equal to valueToMatch.
const obj = { foo: 'bar' }
const secondObj = { foo: 1 }
const propToFind = 'foo'
const valueToMatch = 'bar'
const result = [
R.propEq(propToFind, valueToMatch, obj),
R.propEq(propToFind, valueToMatch, secondObj)
]
// => [true, false]
Try this R.propEq example in Rambda REPL
import { curry } from './curry'
function propEqFn(
propToFind, valueToMatch, obj
){
if (!obj) return false
return obj[ propToFind ] === valueToMatch
}
export const propEq = curry(propEqFn)
import { propEq } from './propEq'
test('happy', () => {
expect(propEq('foo', 'bar')({ foo : 'bar' })).toBeTrue()
expect(propEq('foo', 'bar')({ foo : 'baz' })).toBeFalse()
expect(propEq('foo')('bar')({ foo : 'baz' })).toBeFalse()
expect(propEq(
'foo', 'bar', null
)).toBeFalse()
})
propIs(type: any, name: string, obj: any): boolean
It returns true if property of obj is from target type.
const obj = {a:1, b: 'foo'}
const property = 'foo'
const result = [
R.propIs(String, property, obj),
R.propIs(Number, property, obj)
]
// => [true, false]
Try this R.propIs example in Rambda REPL
import { curry } from './curry'
import { is } from './is'
function propIsFn(
targetPrototype, property, obj
){
return is(targetPrototype, obj[ property ])
}
export const propIs = curry(propIsFn)
import { propIs } from './propIs'
const obj = { value : 1 }
const property = 'value'
test('when true', () => {
expect(propIs(
Number, property, obj
)).toBeTrue()
})
test('when false', () => {
expect(propIs(
String, property, obj
)).toBeFalse()
expect(propIs(
String, property, {}
)).toBeFalse()
})
propOr<T, P extends string>(defaultValue: T, property: P, obj: Partial<Record<P, T>> | undefined): T
It returns either defaultValue or the value of property in obj.
const obj = {a: 1}
const defaultValue = 'DEFAULT_VALUE'
const property = 'a'
const result = [
R.propOr(defaultValue, property, obj),
R.propOr(defaultValue, 'foo', obj)
]
// => [1, 'DEFAULT_VALUE']
Try this R.propOr example in Rambda REPL
import { curry } from './curry'
import { defaultTo } from './defaultTo'
function propOrFn(
defaultValue, property, obj
){
if (!obj) return defaultValue
return defaultTo(defaultValue, obj[ property ])
}
export const propOr = curry(propOrFn)
import { propOr } from './propOr'
test('propOr (result)', () => {
const obj = { a : 1 }
expect(propOr(
'default', 'a', obj
)).toEqual(1)
expect(propOr(
'default', 'notExist', obj
)).toEqual('default')
expect(propOr(
'default', 'notExist', null
)).toEqual('default')
})
test('propOr (currying)', () => {
const obj = { a : 1 }
expect(propOr('default')('a', obj)).toEqual(1)
expect(propOr('default', 'a')(obj)).toEqual(1)
expect(propOr('default')('notExist', obj)).toEqual('default')
expect(propOr('default', 'notExist')(obj)).toEqual('default')
})
props<P extends string, T>(propsToPick: P[], obj: Record<P, T>): T[]
It takes list with properties propsToPick and returns a list with property values in obj.
const result = [
R.props(['a', 'b'], {a:1, c:3})
// => [1, undefined]
Try this R.props example in Rambda REPL
import { _isArray } from './_internals/_isArray'
import { mapArray } from './map'
export function props(propsToPick, obj){
if (arguments.length === 1){
return _obj => props(propsToPick, _obj)
}
if (!_isArray(propsToPick)){
throw new Error('propsToPick is not a list')
}
return mapArray(prop => obj[ prop ], propsToPick)
}
import { props } from './props'
const obj = {
a : 1,
b : 2,
}
const propsToPick = [ 'a', 'c' ]
test('happy', () => {
const result = props(propsToPick, obj)
expect(result).toEqual([ 1, undefined ])
})
test('curried', () => {
const result = props(propsToPick)(obj)
expect(result).toEqual([ 1, undefined ])
})
test('wrong input', () => {
expect(() => props(null)(obj)).toThrow()
})
random(minInclusive: number, maxInclusive: number): number
It returns a random number between min inclusive and max inclusive.
export function random(min, max){
return Math.floor(Math.random() * (max - min + 1)) + min
}
import { random } from './random'
import { range } from './range'
test('when returns true', () => {
range(0, 100).map(() => {
const randomResult = random(1, 10)
expect(randomResult).toBeLessThanOrEqual(10)
expect(randomResult).toBeGreaterThanOrEqual(1)
})
})
range(startInclusive: number, endExclusive: number): number[]
It returns list of numbers between startInclusive to endExclusive markers.
R.range(0, 5)
// => [0, 1, 2, 3, 4]
Try this R.range example in Rambda REPL
export function range(start, end){
if (arguments.length === 1) return _end => range(start, _end)
if (Number.isNaN(Number(start)) || Number.isNaN(Number(end))){
throw new TypeError('Both arguments to range must be numbers')
}
if (end < start) return []
const len = end - start
const willReturn = Array(len)
for (let i = 0; i < len; i++){
willReturn[ i ] = start + i
}
return willReturn
}
import { range } from './range'
test('happy', () => {
expect(range(0, 10)).toEqual([ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 ])
})
test('end range is bigger than start range', () => {
expect(range(7, 3)).toEqual([])
expect(range(5, 5)).toEqual([])
})
test('with bad input', () => {
const throwMessage = 'Both arguments to range must be numbers'
expect(() => range('a', 6)).toThrowWithMessage(Error, throwMessage)
expect(() => range(6, 'z')).toThrowWithMessage(Error, throwMessage)
})
test('curry', () => {
expect(range(0)(10)).toEqual([ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 ])
})
reduce<T, TResult>(reducer: (prev: TResult, current: T, i: number) => TResult, initialValue: TResult, list: T[]): TResult
:boom: It passes index of the list as third argument to
reducerfunction.
const list = [1, 2, 3]
const initialValue = 10
const reducer = (prev, current) => prev * current
const result = R.reduce(reducer, initialValue, list)
// => 60
Try this R.reduce example in Rambda REPL
import { _isArray } from './_internals/_isArray'
import { _keys } from './_internals/_keys'
import { curry } from './curry'
function reduceFn(
reducer, acc, list
){
if (!_isArray(list)){
throw new TypeError('reduce: list must be array or iterable')
}
let index = 0
const len = list.length
while (index < len){
acc = reducer(
acc, list[ index ], index, list
)
index++
}
return acc
}
export const reduce = curry(reduceFn)
import { reduce } from './reduce'
const reducer = (
prev, current, i
) => {
expect(i).toBeNumber()
return prev + current
}
const initialValue = 1
const list = [ 1, 2, 3 ]
test('happy', () => {
expect(reduce(
reducer, initialValue, list
)).toEqual(7)
})
test('with object as iterable', () => {
expect(() =>
reduce(
reducer, initialValue, {
a : 1,
b : 2,
}
)).toThrowWithMessage(TypeError, 'reduce: list must be array or iterable')
})
test('with undefined as iterable', () => {
expect(() => reduce(
reducer, initialValue, undefined
)).toThrowWithMessage(TypeError,
'reduce: list must be array or iterable')
})
reject<T>(predicate: Predicate<T>, list: T[]): T[]
It has the opposite effect of R.filter.
const list = [1, 2, 3, 4]
const obj = {a: 1, b: 2}
const predicate = x => x > 1
const result = [
R.reject(predicate, list)
R.reject(predicate, obj)
]
// => [[1, 2], {a: 1}]
Try this R.reject example in Rambda REPL
import { filter } from './filter'
export function reject(predicate, list){
if (arguments.length === 1) return _list => reject(predicate, _list)
return filter(x => !predicate(x), list)
}
import { reject } from './reject'
const isOdd = n => n % 2 === 1
test('with array', () => {
expect(reject(isOdd)([ 1, 2, 3, 4 ])).toEqual([ 2, 4 ])
})
test('with object', () => {
const obj = {
a : 1,
b : 2,
c : 3,
d : 4,
}
expect(reject(isOdd, obj)).toEqual({
b : 2,
d : 4,
})
})
rejectIndexed<T>(predicate: IndexedPredicate<T>): (x: T[]) => T[]
Same as R.reject, but it passes index/property as second argument to the predicate, when looping over arrays/objects.
const list = [1, 2, 3, 4]
const obj = {a: 1, b: 2}
const result = [
R.reject((x, index) => x > 1, list)
R.reject((x, property) => x > 1, obj)
]
// => [[1], {a: 1}]
Try this R.rejectIndexed example in Rambda REPL
import { filterArray, filterObject } from './filter'
import { _isArray } from './_internals/_isArray'
export function rejectIndexed(predicate, iterable){
if (arguments.length === 1) return _iterable => rejectIndexed(predicate, _iterable)
if (!iterable) throw new Error(`"${iterable}" is not iterable`)
if (_isArray(iterable)) return filterArray((x, i) => !predicate(x, i), iterable, true)
return filterObject((x, prop) => !predicate(x, prop), iterable, true)
}
import { rejectIndexed } from './rejectIndexed'
test('with array', () => {
expect(rejectIndexed((x, i) => {
expect(x).toBeNumber()
expect(i).toBeNumber()
return x % 2 === 1
})([ 1, 2, 3, 4 ])).toEqual([ 2, 4 ])
})
test('with object', () => {
const obj = {
a : 1,
b : 2,
c : 3,
d : 4,
}
expect(rejectIndexed((x, prop) => {
expect(x).toBeNumber()
expect(prop).toBeString()
return x % 2 === 1
}, obj)).toEqual({
b : 2,
d : 4,
})
})
remove(
toRemove: string | RegExp | (string | RegExp)[],
text: string
): string
It will remove all toRemove entries from text sequentially.
toRemove argument can be either a list of strings/regular expressions or a single string/regular expression.
:boom: This is the only case where Rambdax exports clashes with Ramda API, as Ramda has
removemethod. IfRambda.removeis introduced, then this method will be renamed.
const result = remove(
['foo','bar'],
'foo bar baz foo'
)
// => 'baz foo'
Try this R.remove example in Rambda REPL
import { replace } from './replace'
import { type } from './type'
export function remove(inputs, text){
if (arguments.length === 1){
return textHolder => remove(inputs, textHolder)
}
if (type(text) !== 'String'){
throw new Error(`R.remove requires string not ${ type(text) }`)
}
if (type(inputs) !== 'Array'){
return replace(
inputs, '', text
)
}
let textCopy = text
inputs.forEach(singleInput => {
textCopy = replace(
singleInput, '', textCopy
).trim()
})
return textCopy
}
import { remove } from './remove'
test('happy', () => {
const inputs = [ /foo/, /not\shere/, /also/, 'bar' ]
const text = 'foo bar baz foo'
const result = remove(inputs)(text)
const expectedResult = 'baz foo'
expect(result).toEqual(expectedResult)
})
test('with strings + curry', () => {
const inputs = [ 'foo', 'bar' ]
const text = 'foo bar baz foo'
const result = remove(inputs)(text)
const expectedResult = 'baz foo'
expect(result).toEqual(expectedResult)
})
test('with strings and regex', () => {
const inputs = [ /foo/g, 'bar' ]
const text = 'foo bar baz foo'
const result = remove(inputs, text)
const expectedResult = 'baz'
expect(result).toEqual(expectedResult)
})
test('text is not string', () => {
const inputs = [ /foo/g, 'bar' ]
const text = null
expect(() => remove(inputs, text)).toThrowWithMessage(Error,
'R.remove requires string not Null')
})
test('with regexes', () => {
const inputs = [ /foo/g, /bar/ ]
const text = 'foo bar baz foo'
const result = remove(inputs, text)
const expectedResult = 'baz'
expect(result).toEqual(expectedResult)
})
test('with single rule', () => {
const inputs = /foo/g
const text = 'foo bar baz foo'
const result = remove(inputs, text)
const expectedResult = ' bar baz '
expect(result).toEqual(expectedResult)
})
removeIndex<T>(index: number, list: T[]): T[]
It returns a copy of list input with removed index.
const list = [1, 2, 3, 4]
const result = R.removeIndex(1, list)
// => [1, 3, 4]
Try this R.removeIndex example in Rambda REPL
export function removeIndex(index, list){
if (arguments.length === 1) return _list => removeIndex(index, _list)
if (index <= 0) return list.slice(1)
if (index >= list.length - 1) return list.slice(0, list.length - 1)
return [ ...list.slice(0, index), ...list.slice(index + 1) ]
}
import {removeIndex} from './removeIndex'
const list = [1, 2, 3, 4]
test('first or before first index', () => {
expect(removeIndex(-2, list)).toEqual([2, 3, 4])
expect(removeIndex(-2)(list)).toEqual([2, 3, 4])
})
test('last or after last index', () => {
expect(removeIndex(4, list)).toEqual([1, 2, 3])
expect(removeIndex(10, list)).toEqual([1, 2, 3])
})
test('middle index', () => {
expect(removeIndex(1, list)).toEqual([1, 3, 4])
expect(removeIndex(2, list)).toEqual([1, 2, 4])
})
renameProps(rules: object, input: object): object
If property prop of rules is also a property in input, then rename input property to rules[prop].
import { merge } from './merge'
import { omit } from './omit'
export function renameProps(conditions, inputObject){
if (arguments.length === 1){
return inputObjectHolder => renameProps(conditions, inputObjectHolder)
}
const renamed = {}
Object.keys(conditions).forEach(condition => {
if (Object.keys(inputObject).includes(condition)){
renamed[ conditions[ condition ] ] = inputObject[ condition ]
}
})
return merge(renamed, omit(Object.keys(conditions), inputObject))
}
import { renameProps } from './renameProps'
test('renameProps', () => {
const rules = {
f : 'foo',
b : 'bar',
q : 'x',
}
const input = {
f : 1,
b : 2,
a : 3,
}
const result = renameProps(rules, input)
const expectedResult = {
foo : 1,
bar : 2,
a : 3,
}
expect(result).toEqual(expectedResult)
})
test('curry', () => {
const rules = {
f : 'foo',
b : 'bar',
}
const input = {
f : 1,
b : 2,
}
const result = renameProps(rules)(input)
const expectedResult = {
foo : 1,
bar : 2,
}
expect(result).toEqual(expectedResult)
})
repeat<T>(x: T): (timesToRepeat: number) => T[]
R.repeat('foo', 3)
// => ['foo', 'foo', 'foo']
Try this R.repeat example in Rambda REPL
export function repeat(x, timesToRepeat){
if (arguments.length === 1){
return _timesToRepeat => repeat(x, _timesToRepeat)
}
return Array(timesToRepeat).fill(x)
}
import { repeat } from './repeat'
test('repeat', () => {
expect(repeat('')(3)).toEqual([ '', '', '' ])
expect(repeat('foo', 3)).toEqual([ 'foo', 'foo', 'foo' ])
const obj = {}
const arr = repeat(obj, 3)
expect(arr).toEqual([ {}, {}, {} ])
expect(arr[ 0 ] === arr[ 1 ]).toBeTrue()
})
replace(strOrRegex: RegExp | string, replacer: string, str: string): string
It replaces strOrRegex found in str with replacer.
const strOrRegex = /o/g
const result = R.replace(strOrRegex, '|0|', 'foo')
// => 'f|0||0|'
Try this R.replace example in Rambda REPL
import { curry } from './curry'
function replaceFn(
pattern, replacer, str
){
return str.replace(pattern, replacer)
}
export const replace = curry(replaceFn)
import { replace } from './replace'
test('happy', () => {
expect(replace(
'foo', 'yes', 'foo bar baz'
)).toEqual('yes bar baz')
})
test('1', () => {
expect(replace(/\s/g)('|')('foo bar baz')).toEqual('foo|bar|baz')
})
test('2', () => {
expect(replace(/\s/g)('|', 'foo bar baz')).toEqual('foo|bar|baz')
})
test('3', () => {
expect(replace(/\s/g, '|')('foo bar baz')).toEqual('foo|bar|baz')
})
replaceAll(patterns: (RegExp | string)[], replacer: string, input: string): string
Same as R.replace but it accepts array of string and regular expressions instead of a single value.
const replacer = '|'
const patterns = [ /foo/g, 'bar' ]
const input = 'foo bar baz foo bar'
const result = replaceAll(patterns, replacer, input)
// => '| | baz | bar'
Try this R.replaceAll example in Rambda REPL
import { curry } from './curry'
import { ok } from './ok'
function replaceAllFn(
patterns, replacer, input
){
ok(
patterns, replacer, input
)(
Array, String, String
)
let text = input
patterns.forEach(singlePattern => {
text = text.replace(singlePattern, replacer)
})
return text
}
export const replaceAll = curry(replaceAllFn)
import { replaceAll } from './replaceAll'
const replacer = '|'
const patterns = [ /foo/g, 'bar' ]
const input = 'foo bar baz foo bar'
test('happy', () => {
const result = replaceAll(
patterns, replacer, input
)
const expected = '| | baz | bar'
expect(result).toEqual(expected)
})
test('throws when wrong patterns', () => {
expect(() => replaceAll(
{}, replacer, input
)).toThrow()
})
test('throws when wrong input', () => {
expect(() => replaceAll(
patterns, replacer, []
)).toThrow()
})
test('throws when wrong replacer', () => {
expect(() => replaceAll(
patterns, null, input
)).toThrow()
})
reset(): void
:boom:
R.gettermethod contains explanations, tests and source information ofR.reset,R.setterandR.gettermethods.
reverse<T>(input: T[]): T[]
It returns a reversed copy of list or string input.
const result = [
R.reverse('foo'),
R.reverse([1, 2, 3])
]
// => ['oof', [3, 2, 1]
Try this R.reverse example in Rambda REPL
export function reverse(listOrString){
if (typeof listOrString === 'string'){
return listOrString.split('').reverse()
.join('')
}
const clone = listOrString.slice()
return clone.reverse()
}
import { reverse } from './reverse'
test('happy', () => {
expect(reverse([ 1, 2, 3 ])).toEqual([ 3, 2, 1 ])
})
test('with string', () => {
expect(reverse('baz')).toEqual('zab')
})
test('it doesn\'t mutate', () => {
const arr = [ 1, 2, 3 ]
expect(reverse(arr)).toEqual([ 3, 2, 1 ])
expect(arr).toEqual([ 1, 2, 3 ])
})
set<T, U>(lens: Lens, replacer: U, obj: T): T
It returns a copied Object or Array with modified lens focus set to replacer value.
const input = {x: 1, y: 2}
const xLens = R.lensProp('x')
R.set(xLens, 4, input) // => {x: 4, y: 2}
R.set(xLens, 8, input) // => {x: 8, y: 2}
Try this R.set example in Rambda REPL
import { always } from './always'
import { curry } from './curry'
import { over } from './over'
function setFn(
lens, replacer, x
){
return over(
lens, always(replacer), x
)
}
export const set = curry(setFn)
import { assoc } from './assoc'
import { lens } from './lens'
import { lensIndex } from './lensIndex'
import { lensPath } from './lensPath'
import { prop } from './prop'
import { set } from './set'
const testObject = {
foo : 'bar',
baz : {
a : 'x',
b : 'y',
},
}
test('assoc lens', () => {
const assocLens = lens(prop('foo'), assoc('foo'))
const result = set(
assocLens, 'FOO', testObject
)
const expected = {
...testObject,
foo : 'FOO',
}
expect(result).toEqual(expected)
})
test('path lens', () => {
const pathLens = lensPath('baz.a')
const result = set(
pathLens, 'z', testObject
)
const expected = {
...testObject,
baz : {
a : 'z',
b : 'y',
},
}
expect(result).toEqual(expected)
})
test('index lens', () => {
const indexLens = lensIndex(0)
const result = set(
indexLens, 3, [ 1, 2 ]
)
expect(result).toEqual([ 3, 2 ])
})
setter(keyOrObject: string | object, value?: any): void
:boom:
R.gettermethod contains explanations, tests and source information ofR.reset,R.setterandR.gettermethods.
shuffle<T>(list: T[]): T[]
It returns a randomized copy of array.
export function shuffle(arrayRaw){
const array = arrayRaw.concat()
let counter = array.length
while (counter > 0){
const index = Math.floor(Math.random() * counter)
counter--
const temp = array[ counter ]
array[ counter ] = array[ index ]
array[ index ] = temp
}
return array
}
import { range } from './range'
import { shuffle } from './shuffle'
import { uniq } from './uniq'
test('happy', () => {
const list = range(0, 7)
const result = range(0, 300).map(() => shuffle(list))
const allUniq = uniq(result)
expect(allUniq.length > 150).toBeTrue()
})
slice(from: number, to: number, input: string): string
const list = [0, 1, 2, 3, 4, 5]
const str = 'FOO_BAR'
const from = 1
const to = 4
const result = [
R.slice(str, to, list),
R.slice(from, to, list)
]
// => ['OO_', [1, 2, 3]]
Try this R.slice example in Rambda REPL
import { curry } from './curry'
function sliceFn(
from, to, list
){
return list.slice(from, to)
}
export const slice = curry(sliceFn)
import { slice } from './slice'
test('slice', () => {
expect(slice(
1, 3, [ 'a', 'b', 'c', 'd' ]
)).toEqual([ 'b', 'c' ])
expect(slice(
1, Infinity, [ 'a', 'b', 'c', 'd' ]
)).toEqual([ 'b', 'c', 'd' ])
expect(slice(
0, -1, [ 'a', 'b', 'c', 'd' ]
)).toEqual([ 'a', 'b', 'c' ])
expect(slice(
-3, -1, [ 'a', 'b', 'c', 'd' ]
)).toEqual([ 'b', 'c' ])
expect(slice(
0, 3, 'ramda'
)).toEqual('ram')
})
sort<T>(sortFn: (a: T, b: T) => number, list: T[]): T[]
It returns copy of list sorted by sortFn function.
:boom:
sortFnfunction must return a number.
const list = [
{a: 2},
{a: 3},
{a: 1}
]
const sortFn = (x, y) => {
return x.a > y.a ? 1 : -1
}
const result = R.sort(sortFn, list)
const expected = [
{a: 1},
{a: 2},
{a: 3}
]
// => `result` is equal to `expected`
Try this R.sort example in Rambda REPL
export function sort(sortFn, list){
if (arguments.length === 1) return _list => sort(sortFn, _list)
const clone = list.slice()
return clone.sort(sortFn)
}
import { sort } from './sort'
const fn = (a, b) => a > b ? 1 : -1
test('sort', () => {
expect(sort((a, b) => a - b)([ 2, 3, 1 ])).toEqual([ 1, 2, 3 ])
})
test('it doesn\'t mutate', () => {
const list = [ 'foo', 'bar', 'baz' ]
expect(sort(fn, list)).toEqual([ 'bar', 'baz', 'foo' ])
expect(list[ 0 ]).toBe('foo')
expect(list[ 1 ]).toBe('bar')
expect(list[ 2 ]).toBe('baz')
})
sortBy<T>(sortFn: (a: T) => Ord, list: T[]): T[]
It returns copy of list sorted by sortFn function.
:boom:
sortFnfunction must return a value to compare.
const list = [
{a: 2},
{a: 3},
{a: 1}
]
const sortFn = x => x.a
const result = R.sortBy(sortFn, list)
const expected = [
{a: 1},
{a: 2},
{a: 3}
]
// => `result` is equal to `expected`
Try this R.sortBy example in Rambda REPL
export function sortBy(sortFn, list){
if (arguments.length === 1) return _list => sortBy(sortFn, _list)
const clone = list.slice()
return clone.sort((a, b) => {
const aSortResult = sortFn(a)
const bSortResult = sortFn(b)
if (aSortResult === bSortResult) return 0
return aSortResult < bSortResult ? -1 : 1
})
}
import { compose } from './compose'
import { prop } from './prop'
import { sortBy } from './sortBy'
import { toLower } from './toLower'
test('happy', () => {
const input = [ { a : 2 }, { a : 1 }, { a : 1 }, { a : 3 } ]
const expected = [ { a : 1 }, { a : 1 }, { a : 2 }, { a : 3 } ]
const result = sortBy(x => x.a)(input)
expect(result).toEqual(expected)
})
test('with compose', () => {
const alice = {
name : 'ALICE',
age : 101,
}
const bob = {
name : 'Bob',
age : -10,
}
const clara = {
name : 'clara',
age : 314.159,
}
const people = [ clara, bob, alice ]
const sortByNameCaseInsensitive = sortBy(compose(toLower, prop('name')))
expect(sortByNameCaseInsensitive(people)).toEqual([ alice, bob, clara ])
})
sortByPath<T>(sortPath: Path, list: T[]): T[]
It returns copy of list sorted by sortPath value.
As sortPath is passed to R.path, it can be either a string or an array of strings.
const list = [
{a: {b: 2}},
{a: {b: 1}},
{a: {b: 3}}
]
const result = R.sortByPath('a.b', list)
const expected = [
{a: {b: 1}},
{a: {b: 2}},
{a: {b: 3}}
]
// => `result` is equal to `expected`
Try this R.sortByPath example in Rambda REPL
import { path } from './path'
import { sortBy } from './sortBy'
export function sortByPath(sortPath, list){
if (arguments.length === 1) return _list => sortByPath(sortPath, _list)
return sortBy(path(sortPath), list)
}
import { sortByPath } from './sortByPath'
const list = [ { a : { b : 3 } }, { a : { b : 1 } }, { a : { b : 2 } } ]
const sorted = [ { a : { b : 1 } }, { a : { b : 2 } }, { a : { b : 3 } } ]
test('with string as path', () => {
expect(sortByPath('a.b', list)).toEqual(sorted)
})
test('with list of strings as path', () => {
expect(sortByPath([ 'a', 'b' ], list)).toEqual(sorted)
})
test('with string as path - curried', () => {
expect(sortByPath('a.b')(list)).toEqual(sorted)
})
test('with list of strings as path - curried', () => {
expect(sortByPath([ 'a', 'b' ])(list)).toEqual(sorted)
})
sortByProps<T>(sortPaths: string[], list: T[]): T[]
It returns sorted copy of list of objects.
Sorting is done using a list of strings, each representing a path. Two members a and b from list can be sorted if both return a value for a given path. If the value is equal, then the next member of sortPaths(if there is such) will be used in order to find difference between a and b.
const list = [
{a: {b: 2}},
{a: {b: 1}},
{a: {b: 3}}
]
const result = R.sortByPath('a.b', list)
const expected = [
{a: {b: 1}},
{a: {b: 2}},
{a: {b: 3}}
]
// => `result` is equal to `expected`
Try this R.sortByProps example in Rambda REPL
import { path } from './path'
function singleSort(
a, b, sortPaths
){
let toReturn = 0
sortPaths.forEach(singlePath => {
if (toReturn !== 0) return
const aResult = path(singlePath, a)
const bResult = path(singlePath, b)
if ([ aResult, bResult ].includes(undefined)) return
if (aResult === bResult) return
toReturn = aResult > bResult ? 1 : -1
})
return toReturn
}
export function sortByProps(sortPaths, list){
if (arguments.length === 1) return _list => sortByProps(sortPaths, _list)
const clone = list.slice()
clone.sort((a, b) => singleSort(
a, b, sortPaths
))
return clone
}
import { sortByProps } from './sortByProps'
const list = [ { a : { b : 3 } }, { a : { b : 2 } }, { a : { b : 1 } } ]
const sorted = [ { a : { b : 1 } }, { a : { b : 2 } }, { a : { b : 3 } } ]
test('wrong paths are ignored', () => {
expect(sortByProps([ 'foo.bar', 'a.c', 'a.b', 'a.d' ], list)).toEqual(sorted)
})
test('skip sort when path results are equal', () => {
const input = [
{
a : {
b : 0,
c : 2,
},
},
{
a : {
b : 0,
c : 1,
},
},
]
expect(sortByProps([ 'a.b', 'a.d' ], input)).toEqual(input)
})
test('when list is already sorted', () => {
const input = [
{
a : {
b : 0,
c : 1,
},
},
{
a : {
b : 0,
c : 2,
},
},
]
expect(sortByProps([ 'a.b', 'a.c' ])(input)).toEqual(input)
})
sortObject<T>(predicate: SortObjectPredicate<T>, input: { [key: string]: T }): { [keyOutput: string]: T }
It returns a sorted version of input object.
const predicate = (propA, propB, valueA, valueB) => valueA > valueB ? -1 : 1
const result = R.sortObject(predicate, {a:1, b: 4, c: 2})
// => {b: 4, c: 2, a: 1}
Try this R.sortObject example in Rambda REPL
import { sort } from './sort'
export function sortObject(predicate, obj){
if (arguments.length === 1){
return _obj => sortObject(predicate, _obj)
}
const keys = Object.keys(obj)
const sortedKeys = sort((a, b) => predicate(
a, b, obj[ a ], obj[ b ]
), keys)
const toReturn = {}
sortedKeys.forEach(singleKey => {
toReturn[ singleKey ] = obj[ singleKey ]
})
return toReturn
}
import { runTests } from 'helpers-fn'
import { allTrue } from './allTrue'
import { equals } from './equals'
import { sortObject } from './sortObject'
const obj = {
c : 1,
a : 2,
b : 3,
}
const predicateA = (
propA, propB, valueA, valueB
) => propA > propB ? -1 : 1
const expectationA = [ 'c', 'b', 'a' ]
const predicateB = (
propA, propB, valueA, valueB
) => propA < propB ? -1 : 1
const expectationB = [ 'a', 'b', 'c' ]
const predicateC = (
propA, propB, valueA, valueB
) =>
valueA > valueB ? -1 : 1
const expectationC = [ 'b', 'a', 'c' ]
const fn = ([ predicate, expectation ]) => {
const result = sortObject(predicate, obj)
const curriedResult = sortObject(predicate)(obj)
const sortedKeys = Object.keys(result)
const sortedKeysCurried = Object.keys(curriedResult)
const isSameObject = equals(obj, result)
const isSameObjectCurried = equals(obj, curriedResult)
return allTrue(
isSameObject,
isSameObjectCurried,
equals(sortedKeys, expectation),
equals(sortedKeysCurried, expectation)
)
}
const testData = {
label : 'foo',
data : [
{ ok : [ predicateA, expectationA ] },
{ ok : [ predicateB, expectationB ] },
{ ok : [ predicateC, expectationC ] },
],
fn,
}
runTests(testData)
split(separator: string | RegExp): (str: string) => string[]
Curried version of String.prototype.split
const str = 'foo|bar|baz'
const separator = |'
const result = R.split(separator, str))
// => [ 'foo', 'bar', 'baz' ]
Try this R.split example in Rambda REPL
export function split(separator, str){
if (arguments.length === 1) return _str => split(separator, _str)
return str.split(separator)
}
import { split } from './split'
const str = 'foo|bar|baz'
const splitChar = '|'
const expected = [ 'foo', 'bar', 'baz' ]
test('happy', () => {
expect(split(splitChar, str)).toEqual(expected)
})
test('curried', () => {
expect(split(splitChar)(str)).toEqual(expected)
})
splitAt<T>(index: number, input: T[]): [T[], T[]]
It splits string or array at a given index.
const list = [ 1, 2, 3 ]
const result = splitAt(2, list)
// => [[ 1, 2 ], [ 3 ]]
Try this R.splitAt example in Rambda REPL
import { _isArray } from './_internals/_isArray'
import { drop } from './drop'
import { maybe } from './maybe'
import { take } from './take'
export function splitAt(index, input){
if (arguments.length === 1){
return _list => splitAt(index, _list)
}
if (!input) throw new TypeError(`Cannot read property 'slice' of ${ input }`)
if (!_isArray(input) && typeof input !== 'string') return [ [], [] ]
const correctIndex = maybe(
index < 0,
input.length + index < 0 ? 0 : input.length + index,
index
)
return [ take(correctIndex, input), drop(correctIndex, input) ]
}
import { splitAt as splitAtRamda } from 'ramda'
import { splitAt } from './splitAt'
const list = [ 1, 2, 3 ]
const str = 'foo bar'
test('with array', () => {
const result = splitAt(2, list)
expect(result).toEqual([ [ 1, 2 ], [ 3 ] ])
})
test('with array - index is negative number', () => {
const result = splitAt(-6, list)
expect(result).toEqual([ [], list ])
})
test('with array - index is out of scope', () => {
const result = splitAt(4, list)
expect(result).toEqual([ [ 1, 2, 3 ], [] ])
})
test('with string', () => {
const result = splitAt(4, str)
expect(result).toEqual([ 'foo ', 'bar' ])
})
test('with string - index is negative number', () => {
const result = splitAt(-2, str)
expect(result).toEqual([ 'foo b', 'ar' ])
})
test('with string - index is out of scope', () => {
const result = splitAt(10, str)
expect(result).toEqual([ str, '' ])
})
test('with array - index is out of scope', () => {
const result = splitAt(4)(list)
expect(result).toEqual([ [ 1, 2, 3 ], [] ])
})
const badInputs = [ 1, true, /foo/g, {} ]
const throwingBadInputs = [ null, undefined ]
test('with bad inputs', () => {
throwingBadInputs.forEach(badInput => {
expect(() => splitAt(1, badInput)).toThrowWithMessage(TypeError,
`Cannot read property 'slice' of ${ badInput }`)
expect(() => splitAtRamda(1, badInput)).toThrowWithMessage(TypeError,
`Cannot read property 'slice' of ${ badInput }`)
})
badInputs.forEach(badInput => {
const result = splitAt(1, badInput)
const ramdaResult = splitAtRamda(1, badInput)
expect(result).toEqual(ramdaResult)
})
})
splitEvery<T>(sliceLength: number, input: T[]): (T[])[]
It splits input into slices of sliceLength.
const result = [
R.splitEvery(2, [1, 2, 3]),
R.splitEvery(3, 'foobar')
]
const expected = [
[[1, 2], [3]],
['foo', 'bar']
]
// => `result` is equal to `expected`
Try this R.splitEvery example in Rambda REPL
export function splitEvery(sliceLength, listOrString){
if (arguments.length === 1){
return _listOrString => splitEvery(sliceLength, _listOrString)
}
if (sliceLength < 1){
throw new Error('First argument to splitEvery must be a positive integer')
}
const willReturn = []
let counter = 0
while (counter < listOrString.length){
willReturn.push(listOrString.slice(counter, counter += sliceLength))
}
return willReturn
}
import { splitEvery } from './splitEvery'
test('happy', () => {
expect(splitEvery(3, [ 1, 2, 3, 4, 5, 6, 7 ])).toEqual([
[ 1, 2, 3 ],
[ 4, 5, 6 ],
[ 7 ],
])
expect(splitEvery(3)('foobarbaz')).toEqual([ 'foo', 'bar', 'baz' ])
})
test('with bad input', () => {
expect(() =>
expect(splitEvery(0)('foo')).toEqual([ 'f', 'o', 'o' ])).toThrowWithMessage(Error,
'First argument to splitEvery must be a positive integer')
})
splitWhen<T, U>(predicate: Predicate<T>, list: U[]): (U[])[]
It splits list to two arrays according to a predicate function.
The first array contains all members of list before predicate returns true.
const list = [1, 2, 1, 2]
const result = R.splitWhen(R.equals(2), list)
// => [[1], [2, 1, 2]]
Try this R.splitWhen example in Rambda REPL
export function splitWhen(predicate, input){
if (arguments.length === 1){
return _input => splitWhen(predicate, _input)
}
if (!input)
throw new TypeError(`Cannot read property 'length' of ${ input }`)
const preFound = []
const postFound = []
let found = false
let counter = -1
while (counter++ < input.length - 1){
if (found){
postFound.push(input[ counter ])
} else if (predicate(input[ counter ])){
postFound.push(input[ counter ])
found = true
} else {
preFound.push(input[ counter ])
}
}
return [ preFound, postFound ]
}
import { splitWhen as splitWhenRamda } from 'ramda'
import { equals } from './equals'
import { splitWhen } from './splitWhen'
const list = [ 1, 2, 1, 2 ]
test('happy', () => {
const result = splitWhen(equals(2), list)
expect(result).toEqual([ [ 1 ], [ 2, 1, 2 ] ])
})
test('when predicate returns false', () => {
const result = splitWhen(equals(3))(list)
expect(result).toEqual([ list, [] ])
})
const badInputs = [ 1, true, /foo/g, {} ]
const throwingBadInputs = [ null, undefined ]
test('with bad inputs', () => {
throwingBadInputs.forEach(badInput => {
expect(() => splitWhen(equals(2), badInput)).toThrowWithMessage(TypeError,
`Cannot read property 'length' of ${ badInput }`)
expect(() => splitWhenRamda(equals(2), badInput)).toThrowWithMessage(TypeError,
`Cannot read property 'length' of ${ badInput }`)
})
badInputs.forEach(badInput => {
const result = splitWhen(equals(2), badInput)
const ramdaResult = splitWhenRamda(equals(2), badInput)
expect(result).toEqual(ramdaResult)
})
})
startsWith(target: string, str: string): boolean
Curried version of String.prototype.startsWith
:boom: It doesn't work with arrays unlike its corresponding Ramda method.
const str = 'foo-bar'
const result = [
R.startsWith('foo', str),
R.startsWith('bar', str)
]
// => [true, false]
Try this R.startsWith example in Rambda REPL
export function startsWith(target, str){
if (arguments.length === 1) return _str => startsWith(target, _str)
return str.startsWith(target)
}
import { startsWith } from './startsWith'
test('true', () => {
const result = startsWith('foo', 'foo-bar')
expect(result).toBeTrue()
})
test('false', () => {
const result = startsWith('baz')('foo-bar')
expect(result).toBeFalse()
})
Curried version of x - y
const x = 3
const y = 1
R.subtract(x, y)
// => 2
Try this R.subtract example in Rambda REPL
sum(list: number[]): number
R.sum([1, 2, 3, 4, 5])
// => 15
Try this R.sum example in Rambda REPL
export function sum(list){
return list.reduce((prev, current) => prev + current, 0)
}
import { sum } from './sum'
test('happy', () => {
expect(sum([ 1, 2, 3, 4, 5 ])).toBe(15)
})
switcher<T>(valueToMatch: any): Switchem<T>
Edited fork of Switchem library.
The method return a value if the matched option is a value.
If the matched option is a function, then R.switcher returns a function which expects input. Tests of the method explain it better than this short description.
R.equals is used to determine equality.
const valueToMatch = {foo: 1}
const result = R.switcher(valueToMatch)
.is('baz', 'is baz')
.is(x => typeof x === 'boolean', 'is boolean')
.is({foo: 1}, 'Property foo is 1')
.default('is bar')
// => 'Property foo is 1'
Try this R.switcher example in Rambda REPL
import { equals } from './equals'
const NO_MATCH_FOUND = Symbol ? Symbol('NO_MATCH_FOUND') : undefined
const getMatchingKeyValuePair = (
cases, testValue, defaultValue
) => {
let iterationValue
for (let index = 0; index < cases.length; index++){
iterationValue = cases[ index ].test(testValue)
if (iterationValue !== NO_MATCH_FOUND){
return iterationValue
}
}
return defaultValue
}
const isEqual = (testValue, matchValue) => {
const willReturn =
typeof testValue === 'function' ?
testValue(matchValue) :
equals(testValue, matchValue)
return willReturn
}
const is = (testValue, matchResult = true) => ({
key : testValue,
test : matchValue =>
isEqual(testValue, matchValue) ? matchResult : NO_MATCH_FOUND,
})
class Switchem{
constructor(
defaultValue, cases, willMatch
){
if (cases === undefined && willMatch === undefined){
this.cases = []
this.defaultValue = undefined
this.willMatch = defaultValue
} else {
this.cases = cases
this.defaultValue = defaultValue
this.willMatch = willMatch
}
return this
}
default(defaultValue){
const holder = new Switchem(
defaultValue, this.cases, this.willMatch
)
return holder.match(this.willMatch)
}
is(testValue, matchResult){
return new Switchem(
this.defaultValue,
[ ...this.cases, is(testValue, matchResult) ],
this.willMatch
)
}
match(matchValue){
return getMatchingKeyValuePair(
this.cases, matchValue, this.defaultValue
)
}
}
export function switcher(input){
return new Switchem(input)
}
import { add } from './add'
import { switcher } from './switcher'
import { tap } from './tap'
import { trim } from './trim'
test('with undefined', () => {
const result = switcher(undefined)
.is(x => x === 0, '0')
.is(x => x === undefined, 'UNDEFINED')
.default('3')
expect(result).toEqual('UNDEFINED')
})
test('happy', () => {
const a = true
const b = false
const result = switcher([ a, b ])
.is([ false, false ], '0')
.is([ false, true ], '1')
.is([ true, true ], '2')
.default('3')
expect(result).toEqual('3')
})
test('can compare objects', () => {
const result = switcher({ a : 1 })
.is({ a : 1 }, 'it is object')
.is('baz', 'it is baz')
.default('it is default')
expect(result).toEqual('it is object')
})
test('options are mixture of functions and values - input match function', () => {
const fn = switcher('foo').is('bar', 1)
.is('foo', add(1))
.default(1000)
expect(fn(2)).toEqual(3)
})
test('options are mixture of functions and values - input match value', () => {
const result = switcher('bar').is('bar', 1)
.is('foo', add(1))
.default(1000)
expect(result).toBe(1)
})
test('return function if all options are functions', () => {
const fn = switcher('foo').is('bar', tap)
.is('foo', add(1))
.default(trim)
expect(fn(2)).toEqual(3)
})
const switchFn = input =>
switcher(input)
.is(x => x.length && x.length === 7, 'has length of 7')
.is('baz', 'it is baz')
.default('it is default')
test('works with function as condition', () => {
expect(switchFn([ 0, 1, 2, 3, 4, 5, 6 ])).toEqual('has length of 7')
})
test('works with string as condition', () => {
expect(switchFn('baz')).toEqual('it is baz')
})
test('fallback to default input when no matches', () => {
expect(switchFn(1)).toEqual('it is default')
})
symmetricDifference<T>(x: T[], y: T[]): T[]
It returns a merged list of x and y with all equal elements removed.
R.equals is used to determine equality.
const x = [ 1, 2, 3, 4 ]
const y = [ 3, 4, 5, 6 ]
const result = symmetricDifference(x, y)
// => [ 1, 2, 5, 6 ]
Try this R.symmetricDifference example in Rambda REPL
import { concat } from './concat'
import { filter } from './filter'
import { includes } from './includes'
export function symmetricDifference(x, y){
if (arguments.length === 1){
return _y => symmetricDifference(x, _y)
}
return concat(filter(value => !includes(value, y), x),
filter(value => !includes(value, x), y))
}
import { symmetricDifference } from './symmetricDifference'
test('symmetricDifference', () => {
const list1 = [ 1, 2, 3, 4 ]
const list2 = [ 3, 4, 5, 6 ]
expect(symmetricDifference(list1)(list2)).toEqual([ 1, 2, 5, 6 ])
expect(symmetricDifference([], [])).toEqual([])
})
test('symmetricDifference with objects', () => {
const list1 = [ { id : 1 }, { id : 2 }, { id : 3 }, { id : 4 } ]
const list2 = [ { id : 3 }, { id : 4 }, { id : 5 }, { id : 6 } ]
expect(symmetricDifference(list1)(list2)).toEqual([
{ id : 1 },
{ id : 2 },
{ id : 5 },
{ id : 6 },
])
})
T(): boolean
R.T()
// => true
Try this R.T example in Rambda REPL
export function T(){
return true
}
tail<T>(input: T[]): T[]
It returns all but the first element of input.
const result = [
R.tail([1, 2, 3]),
R.tail('foo')
]
// => [[2, 3], 'oo']
Try this R.tail example in Rambda REPL
import { drop } from './drop'
export function tail(listOrString){
return drop(1, listOrString)
}
import { tail } from './tail'
test('tail', () => {
expect(tail([ 1, 2, 3 ])).toEqual([ 2, 3 ])
expect(tail([ 1, 2 ])).toEqual([ 2 ])
expect(tail([ 1 ])).toEqual([])
expect(tail([])).toEqual([])
expect(tail('abc')).toEqual('bc')
expect(tail('ab')).toEqual('b')
expect(tail('a')).toEqual('')
expect(tail('')).toEqual('')
})
take<T>(howMany: number, input: T[]): T[]
It returns the first howMany elements of input.
const howMany = 2
const result = [
R.take(howMany, [1, 2, 3]),
R.take(howMany, 'foobar'),
]
// => [[1, 2], 'fo']
Try this R.take example in Rambda REPL
import baseSlice from './_internals/baseSlice'
export function take(howMany, listOrString){
if (arguments.length === 1)
return _listOrString => take(howMany, _listOrString)
if (howMany < 0) return listOrString.slice()
if (typeof listOrString === 'string') return listOrString.slice(0, howMany)
return baseSlice(
listOrString, 0, howMany
)
}
import { take } from './take'
test('happy', () => {
const arr = [ 'foo', 'bar', 'baz' ]
expect(take(1, arr)).toEqual([ 'foo' ])
expect(arr).toEqual([ 'foo', 'bar', 'baz' ])
expect(take(2)([ 'foo', 'bar', 'baz' ])).toEqual([ 'foo', 'bar' ])
expect(take(3, [ 'foo', 'bar', 'baz' ])).toEqual([ 'foo', 'bar', 'baz' ])
expect(take(4, [ 'foo', 'bar', 'baz' ])).toEqual([ 'foo', 'bar', 'baz' ])
expect(take(3)('rambda')).toEqual('ram')
})
test('with negative index', () => {
expect(take(-1, [ 1, 2, 3 ])).toEqual([ 1, 2, 3 ])
expect(take(-Infinity, [ 1, 2, 3 ])).toEqual([ 1, 2, 3 ])
})
test('with zero index', () => {
expect(take(0, [ 1, 2, 3 ])).toEqual([])
})
takeLast<T>(howMany: number, input: T[]): T[]
It returns the last howMany elements of input.
const howMany = 2
const result = [
R.takeLast(howMany, [1, 2, 3]),
R.takeLast(howMany, 'foobar'),
]
// => [[2, 3], 'ar']
Try this R.takeLast example in Rambda REPL
import baseSlice from './_internals/baseSlice'
export function takeLast(howMany, listOrString){
if (arguments.length === 1)
return _listOrString => takeLast(howMany, _listOrString)
const len = listOrString.length
if (howMany < 0) return listOrString.slice()
let numValue = howMany > len ? len : howMany
if (typeof listOrString === 'string')
return listOrString.slice(len - numValue)
numValue = len - numValue
return baseSlice(
listOrString, numValue, len
)
}
import { takeLast } from './takeLast'
test('with arrays', () => {
expect(takeLast(1, [ 'foo', 'bar', 'baz' ])).toEqual([ 'baz' ])
expect(takeLast(2)([ 'foo', 'bar', 'baz' ])).toEqual([ 'bar', 'baz' ])
expect(takeLast(3, [ 'foo', 'bar', 'baz' ])).toEqual([ 'foo', 'bar', 'baz' ])
expect(takeLast(4, [ 'foo', 'bar', 'baz' ])).toEqual([ 'foo', 'bar', 'baz' ])
expect(takeLast(10, [ 'foo', 'bar', 'baz' ])).toEqual([ 'foo', 'bar', 'baz' ])
})
test('with strings', () => {
expect(takeLast(3, 'rambda')).toEqual('bda')
expect(takeLast(7, 'rambda')).toEqual('rambda')
})
test('with negative index', () => {
expect(takeLast(-1, [ 1, 2, 3 ])).toEqual([ 1, 2, 3 ])
expect(takeLast(-Infinity, [ 1, 2, 3 ])).toEqual([ 1, 2, 3 ])
})
takeLastWhile(predicate: (x: string) => boolean, input: string): string
const result = R.takeLastWhile(
x => x > 2,
[1, 2, 3, 4]
)
// => [3, 4]
Try this R.takeLastWhile example in Rambda REPL
import { _isArray } from './_internals/_isArray'
export function takeLastWhile(predicate, input){
if (arguments.length === 1){
return _input => takeLastWhile(predicate, _input)
}
if (input.length === 0) return input
let found = false
const toReturn = []
let counter = input.length
while (!found || counter === 0){
counter--
if (predicate(input[ counter ]) === false){
found = true
} else if (!found){
toReturn.push(input[ counter ])
}
}
return _isArray(input) ? toReturn.reverse() : toReturn.reverse().join('')
}
import { takeLastWhile } from './takeLastWhile'
const assert = require('assert')
const list = [ 1, 2, 3, 4 ]
test('happy', () => {
const predicate = x => x > 2
const result = takeLastWhile(predicate, list)
expect(result).toEqual([ 3, 4 ])
})
test('predicate is always true', () => {
const predicate = x => x > 0
const result = takeLastWhile(predicate)(list)
expect(result).toEqual(list)
})
test('predicate is always false', () => {
const predicate = x => x < 0
const result = takeLastWhile(predicate, list)
expect(result).toEqual([])
})
test('with string', () => {
const result = takeLastWhile(x => x !== 'F', 'FOOBAR')
expect(result).toEqual('OOBAR')
})
takeUntil<T>(predicate: (x: T) => boolean, list: T[]): T[]
const list = [1, 2, 3, 4, 5]
const predicate = x => x > 3
const result = R.takeUntil(predicate, list)
// => [1, 2, 3]
Try this R.takeUntil example in Rambda REPL
export function takeUntil(predicate, list){
const toReturn = []
let stopFlag = false
let counter = -1
while (stopFlag === false && counter++ < list.length - 1){
if (predicate(list[ counter ])){
stopFlag = true
} else {
toReturn.push(list[ counter ])
}
}
return toReturn
}
import { takeUntil } from './takeUntil'
const list = [ 1, 2, 3, 4, 5, 6 ]
test('happy', () => {
const result = takeUntil(x => x > 3, list)
expect(result).toEqual([ 1, 2, 3 ])
})
test('predicate always returns true', () => {
const result = takeUntil(x => x < 10, list)
expect(result).toEqual([])
})
test('predicate always returns false', () => {
const result = takeUntil(x => x > 10, list)
expect(result).toEqual(list)
})
const list = [1, 2, 3, 4]
const predicate = x => x < 3
const result = R.takeWhile(predicate, list)
// => [1, 2]
Try this R.takeWhile example in Rambda REPL
tap<T>(fn: (x: T) => void, input: T): T
It applies function fn to input x and returns x.
One use case is debuging in the middle of R.compose.
const list = [1, 2, 3]
R.compose(
R.map(x => x * 2)
R.tap(console.log),
R.filter(x => x > 1)
)(list)
// => `2` and `3` will be logged
Try this R.tap example in Rambda REPL
export function tap(fn, x){
if (arguments.length === 1) return _x => tap(fn, _x)
fn(x)
return x
}
import { tap } from './tap'
test('tap', () => {
let a = 1
const sayX = x => a = x
expect(tap(sayX, 100)).toEqual(100)
expect(tap(sayX)(100)).toEqual(100)
expect(a).toEqual(100)
})
tapAsync<T>(fn: Func<any> | Promise<any>, input: T): T
Asynchronous version of R.tap.
async function tapAsyncFn(fn, input){
await fn(input)
return input
}
export function tapAsync(fn, input){
if (arguments.length === 1){
return async _input => tapAsyncFn(fn, _input)
}
return new Promise((resolve, reject) => {
tapAsyncFn(fn, input).then(resolve)
.catch(reject)
})
}
import { delay } from './delay'
import { pipedAsync } from './pipedAsync'
import { tapAsync } from './tapAsync'
test('happy', async () => {
const result = await tapAsync(delay, 1)
expect(result).toEqual(1)
})
test('complex', async () => {
let marker = false
const fn = () => marker = true
const result = await pipedAsync(
1,
async x => {
await delay(100)
return x + 1
},
tapAsync(fn),
x => x + 1
)
expect(marker).toBeTrue()
expect(result).toEqual(3)
})
test(regExpression: RegExp): (str: string) => boolean
It determines whether str matches regExpression.
R.test(/^f/, 'foo')
// => true
Try this R.test example in Rambda REPL
export function test(pattern, str){
if (arguments.length === 1) return _str => test(pattern, _str)
if (typeof pattern === 'string'){
throw new TypeError(`‘test’ requires a value of type RegExp as its first argument; received "${ pattern }"`)
}
return str.search(pattern) !== -1
}
import { test as testMethod } from './test'
test('happy', () => {
expect(testMethod(/^x/, 'xyz')).toBeTrue()
expect(testMethod(/^y/)('xyz')).toBeFalse()
})
test('throws if first argument is not regex', () => {
expect(() => testMethod('foo', 'bar')).toThrowWithMessage(TypeError,
'‘test’ requires a value of type RegExp as its first argument; received "foo"')
})
throttle<T, U>(fn: (input: T) => U, ms: number): (input: T) => U
It creates a throttled function that invokes fn maximum once for a period of milliseconds.
let counter = 0
const inc = () => {
counter++
}
const throttledInc = R.throttle(inc, 800)
const result = async () => {
throttledInc()
await R.delay(500)
throttledInc()
return counter
}
// `result` resolves to `1`
Try this R.throttle example in Rambda REPL
export function throttle(fn, ms){
let wait = false
return function (...input){
if (!wait){
fn.apply(null, input)
wait = true
setTimeout(() => {
wait = false
}, ms)
}
}
}
import { delay } from './delay'
import { throttle } from './throttle'
test('', async () => {
let counter = 0
let aHolder
let bHolder
const inc = (a, b) => {
aHolder = a
bHolder = b
counter++
}
const incWrapped = throttle(inc, 1000)
incWrapped(1, 2)
await delay(500)
incWrapped(2, 3)
incWrapped(3, 4)
expect(counter).toBe(1)
expect(aHolder).toBe(1)
expect(bHolder).toBe(2)
await delay(1000)
incWrapped(5, 6)
expect(counter).toBe(2)
expect(aHolder).toBe(5)
expect(bHolder).toBe(6)
})
times<T>(fn: (i: number) => T, howMany: number): T[]
It returns the result of applying function fn over members of range array.
The range array includes numbers between 0 and howMany(exclusive).
const fn = x => x * 2
const howMany = 5
R.times(fn, howMany)
// => [0, 2, 4, 6, 8]
Try this R.times example in Rambda REPL
import { map } from './map'
import { range } from './range'
export function times(fn, howMany){
if (arguments.length === 1) return _howMany => times(fn, _howMany)
if (!Number.isInteger(howMany) || howMany < 0){
throw new RangeError('n must be an integer')
}
return map(fn, range(0, howMany))
}
import assert from 'assert'
import { identity } from './identity'
import { times } from './times'
test('happy', () => {
const result = times(identity, 5)
expect(result).toEqual([ 0, 1, 2, 3, 4 ])
})
test('with bad input', () => {
assert.throws(() => {
times(3)('cheers!')
}, RangeError)
assert.throws(() => {
times(identity, -1)
}, RangeError)
})
test('curry', () => {
const result = times(identity)(5)
expect(result).toEqual([ 0, 1, 2, 3, 4 ])
})
toDecimal(num: number, charsAfterDecimalPoint?: number): number
R.toDecimal(2.45464,2) // => 2.45
Try this R.toDecimal example in Rambda REPL
export function toDecimal(number, charsAfterDecimalPoint = 2){
return Number(parseFloat(String(number)).toFixed(charsAfterDecimalPoint))
}
import { toDecimal } from './toDecimal'
test('happy', () => {
expect(toDecimal(2.2789, 1)).toBe(2.3)
expect(toDecimal(2.2789, 3)).toBe(2.279)
expect(toDecimal(2, 3)).toBe(2)
expect(toDecimal(2.2789)).toBe(2.28)
expect(toDecimal(2.45464)).toBe(2.45)
})
toLower(str: string): string
R.toLower('FOO')
// => 'foo'
Try this R.toLower example in Rambda REPL
export function toLower(str){
return str.toLowerCase()
}
import { toLower } from './toLower'
test('toLower', () => {
expect(toLower('FOO|BAR|BAZ')).toEqual('foo|bar|baz')
})
toPairs<S>(obj: { [k: string]: S } | { [k: number]: S }): ([string, S])[]
It transforms an object to a list.
const list = {
a : 1,
b : 2,
c : [ 3, 4 ],
}
const expected = [ [ 'a', 1 ], [ 'b', 2 ], [ 'c', [ 3, 4 ] ] ]
const result = R.toPairs(list)
// => `result` is equal to `expected`
Try this R.toPairs example in Rambda REPL
export function toPairs(obj){
return Object.entries(obj)
}
import { toPairs } from './toPairs'
const obj = {
a : 1,
b : 2,
c : [ 3, 4 ],
}
const expected = [
[ 'a', 1 ],
[ 'b', 2 ],
[ 'c', [ 3, 4 ] ],
]
test('happy', () => {
expect(toPairs(obj)).toEqual(expected)
})
toString<T>(x: T): string
R.toString([1, 2])
// => '1,2'
Try this R.toString example in Rambda REPL
export function toString(x){
return x.toString()
}
import { toString } from './toString'
test('happy', () => {
expect(toString([ 1, 2, 3 ])).toEqual('1,2,3')
})
toUpper(str: string): string
R.toUpper('foo')
// => 'FOO'
Try this R.toUpper example in Rambda REPL
export function toUpper(str){
return str.toUpperCase()
}
import { toUpper } from './toUpper'
test('toUpper', () => {
expect(toUpper('foo|bar|baz')).toEqual('FOO|BAR|BAZ')
})
transpose<T>(list: (T[])[]): (T[])[]
const list = [[10, 11], [20], [], [30, 31, 32]]
const expected = [[10, 20, 30], [11, 31], [32]]
const result = R.transpose(list)
// => `result` is equal to `expected`
Try this R.transpose example in Rambda REPL
import { _isArray } from './_internals/_isArray'
export function transpose(array){
return array.reduce((acc, el) => {
el.forEach((nestedEl, i) =>
_isArray(acc[ i ]) ? acc[ i ].push(nestedEl) : acc.push([ nestedEl ]))
return acc
}, [])
}
import { transpose } from './transpose'
test('happy', () => {
const input = [
[ 'a', 1 ],
[ 'b', 2 ],
[ 'c', 3 ],
]
expect(transpose(input)).toEqual([
[ 'a', 'b', 'c' ],
[ 1, 2, 3 ],
])
})
test('when rows are shorter', () => {
const actual = transpose([ [ 10, 11 ], [ 20 ], [], [ 30, 31, 32 ] ])
const expected = [ [ 10, 20, 30 ], [ 11, 31 ], [ 32 ] ]
expect(actual).toEqual(expected)
})
test('with empty array', () => {
expect(transpose([])).toEqual([])
})
test('array with falsy values', () => {
const actual = transpose([
[ true, false, undefined, null ],
[ null, undefined, false, true ],
])
const expected = [
[ true, null ],
[ false, undefined ],
[ undefined, false ],
[ null, true ],
]
expect(actual).toEqual(expected)
})
trim(str: string): string
R.trim(' foo ')
// => 'foo'
Try this R.trim example in Rambda REPL
export function trim(str){
return str.trim()
}
import { trim } from './trim'
test('trim', () => {
expect(trim(' foo ')).toEqual('foo')
})
tryCatch<T, U>(
fn: (input: T) => U,
fallback: U
): (input: T) => U
It returns function that runs fn in try/catch block. If there was an error, then fallback is used to return the result. Note that fn can be value or asynchronous/synchronous function(unlike Ramda where fallback can only be a synchronous function).
:boom: Please check the tests of
R.tryCatchto fully understand how this method works.
const fn = x => x.foo
const result = [
R.tryCatch(fn, false)(null),
R.tryCatch(fn, false)({foo: 'bar'})
]
// => [false, 'bar']
Try this R.tryCatch example in Rambda REPL
import { isFunction } from './isFunction'
export function tryCatch(fn, fallback){
if (!isFunction(fn)){
throw new Error(`R.tryCatch | fn '${ fn }'`)
}
const passFallback = isFunction(fallback)
return (...inputs) => {
try {
return fn(...inputs)
} catch (e){
return passFallback ? fallback(e, ...inputs) : fallback
}
}
}
import { tryCatch as tryCatchRamda } from 'ramda'
import { compareCombinations } from './_internals/testUtils'
import { prop } from './prop'
import { tryCatch } from './tryCatch'
test('happy', () => {
const fn = () => {
throw new Error('foo')
}
const result = tryCatch(fn, () => true)()
expect(result).toBeTrue()
})
test('when fallback is used', () => {
const fn = x => x.x
expect(tryCatch(fn, false)(null)).toBeFalse()
})
test('with json parse', () => {
const good = () => JSON.parse(JSON.stringify({ a : 1 }))
const bad = () => JSON.parse('a{a')
expect(tryCatch(good, 1)()).toEqual({ a : 1 })
expect(tryCatch(bad, 1)()).toBe(1)
})
test('when fallback is function', () => {
const fn = x => x.x
expect(tryCatch(fn, () => 1)(null)).toBe(1)
})
test('when fn is used', () => {
const fn = prop('x')
expect(tryCatch(fn, false)({})).toBe(undefined)
expect(tryCatch(fn, false)({ x : 1 })).toBe(1)
})
test('fallback receives error object and all initial inputs', () => {
function thrower(
a, b, c
){
void c
throw new Error('throwerError')
}
function catchFn(
e, a, b, c
){
return [ e.message, a, b, c ].join('|')
}
const willThrow = tryCatch(thrower, catchFn)
const result = willThrow(
'A', 'B', 'C'
)
expect(result).toBe('throwerError|A|B|C')
})
test('fallback receives error object', () => {
function throwFn(){
throw new Error(10)
}
function eCatcher(
e, a, b
){
return e.message
}
const willThrow = tryCatch(throwFn, eCatcher)
expect(willThrow([])).toBe('10')
expect(willThrow([ {}, {}, {} ])).toBe('10')
})
const possibleFns = [
null,
() => 1,
() => 0,
() => JSON.parse('{a:1'),
() => {
const x = {}
return x.x
},
x => x.foo,
() => {
throw new Error('foo')
},
]
const possibleCatchers = [
null,
e => e.message.length,
(e, ...inputs) => `${ e.message.length } ${ inputs.length }`,
() => {
throw new Error('bar')
},
]
const possibleInputs = [ null, {}, { foo : 1 } ]
describe('brute force', () => {
compareCombinations({
returnsFunctionFlag : true,
firstInput : possibleFns,
callback : errorsCounters => {
expect(errorsCounters).toMatchInlineSnapshot(`
Object {
"ERRORS_MESSAGE_MISMATCH": 0,
"ERRORS_TYPE_MISMATCH": 12,
"RESULTS_MISMATCH": 0,
"SHOULD_NOT_THROW": 0,
"SHOULD_THROW": 7,
}
`)
},
secondInput : possibleCatchers,
thirdInput : possibleInputs,
fn : tryCatch,
fnRamda : tryCatchRamda,
})
})
tryCatchAsync<T>(
fn: (input: any) => Promise<T>,
fallback: T
): (input: any) => Promise<T>
It returns function that runs fn in try/catch block. If there was an error, then fallback is used to return the result.
const x = {foo: 1}
const fnFoo = async () => x.foo
const fnBar = async () => x.bar
const result = await Promise.all([
R.tryCatchAsync (fnFoo, false)(),
R.tryCatchAsync(fnBar, false)()
])
// => [1, false]
Try this R.tryCatchAsync example in Rambda REPL
import { isFunction } from './isFunction'
import { isPromise } from './isPromise'
export function tryCatchAsync(fn, fallback){
return (...inputs) =>
new Promise(resolve => {
fn(...inputs)
.then(resolve)
.catch(err => {
if (!isFunction(fallback)){
return resolve(fallback)
}
if (!isPromise(fallback)){
return resolve(fallback(err, ...inputs))
}
fallback(err, ...inputs).then(resolve)
.catch(resolve)
})
})
}
import { delay } from './delay'
import { tryCatchAsync } from './tryCatchAsync'
test('when fallback is function', async () => {
const fn = async x => x.x
const result = await tryCatchAsync(fn, () => 1)(null)
expect(result).toBe(1)
})
test('when fallback throws', async () => {
const fn = async x => x.x
const fallback = async (err, xx) => xx.y
const result = await tryCatchAsync(fn, fallback)(null)
expect(result.message).toMatchInlineSnapshot('"Cannot read property \'y\' of null"')
})
test('fallback is not used', async () => {
const fn = async x => x.x
expect(tryCatchAsync(fn, false)({ x : 1 })).resolves.toBe(1)
})
test('fallback receives error object and all initial inputs', async () => {
async function thrower(
a, b, c
){
void c
throw new Error('throwerError')
}
function catchFn(
e, a, b, c
){
return [ e.message, a, b, c ].join('|')
}
const willThrow = tryCatchAsync(thrower, catchFn)
const result = await willThrow(
'A', 'B', 'C'
)
expect(result).toBe('throwerError|A|B|C')
})
test('when async + value fallback', async () => {
const fn = async () => {
await delay(100)
return JSON.parse('{a:')
}
const result = await tryCatchAsync(fn, 'fallback')(100)
expect(result).toBe('fallback')
})
type(x: any): RambdaTypes
It accepts any input and it returns its type.
:boom:
NaN,PromiseandAsyncare types specific for Rambda.
R.type(() => {}) // => 'Function'
R.type(async () => {}) // => 'Async'
R.type([]) // => 'Array'
R.type({}) // => 'Object'
R.type('foo') // => 'String'
R.type(1) // => 'Number'
R.type(true) // => 'Boolean'
R.type(null) // => 'Null'
R.type(/[A-z]/) // => 'RegExp'
R.type('foo'*1) // => 'NaN'
const delay = ms => new Promise(resolve => {
setTimeout(function () {
resolve()
}, ms)
})
R.type(delay) // => 'Promise'
Try this R.type example in Rambda REPL
import { _isArray } from './_internals/_isArray'
export function type(input){
const typeOf = typeof input
if (input === null){
return 'Null'
} else if (input === undefined){
return 'Undefined'
} else if (typeOf === 'boolean'){
return 'Boolean'
} else if (typeOf === 'number'){
return Number.isNaN(input) ? 'NaN' : 'Number'
} else if (typeOf === 'string'){
return 'String'
} else if (_isArray(input)){
return 'Array'
} else if (typeOf === 'symbol'){
return 'Symbol'
} else if (input instanceof RegExp){
return 'RegExp'
}
const asStr = input && input.toString ? input.toString() : ''
if ([ 'true', 'false' ].includes(asStr)) return 'Boolean'
if (!Number.isNaN(Number(asStr))) return 'Number'
if (asStr.startsWith('async')) return 'Async'
if (asStr === '[object Promise]') return 'Promise'
if (typeOf === 'function') return 'Function'
if (input instanceof String) return 'String'
return 'Object'
}
import { type as ramdaType } from 'ramda'
import { type } from './type'
test('with symbol', () => {
expect(type(Symbol())).toBe('Symbol')
})
test('with simple promise', () => {
expect(type(Promise.resolve(1))).toBe('Promise')
})
test('with new Boolean', () => {
expect(type(new Boolean(true))).toBe('Boolean')
})
test('with new String', () => {
expect(type(new String('I am a String object'))).toEqual('String')
})
test('with new Number', () => {
expect(type(new Number(1))).toBe('Number')
})
test('with new promise', () => {
const delay = ms =>
new Promise(resolve => {
setTimeout(() => {
resolve(ms + 110)
}, ms)
})
expect(type(delay(10))).toEqual('Promise')
})
test('async function', () => {
expect(type(async () => {})).toEqual('Async')
})
test('async arrow', () => {
const asyncArrow = async () => {}
expect(type(asyncArrow)).toBe('Async')
})
test('function', () => {
const fn1 = () => {}
const fn2 = function (){}
function fn3(){}
;[ () => {}, fn1, fn2, fn3 ].map(val => {
expect(type(val)).toEqual('Function')
})
})
test('object', () => {
expect(type({})).toEqual('Object')
})
test('number', () => {
expect(type(1)).toEqual('Number')
})
test('boolean', () => {
expect(type(false)).toEqual('Boolean')
})
test('string', () => {
expect(type('foo')).toEqual('String')
})
test('null', () => {
expect(type(null)).toEqual('Null')
})
test('array', () => {
expect(type([])).toEqual('Array')
expect(type([ 1, 2, 3 ])).toEqual('Array')
})
test('regex', () => {
expect(type(/\s/g)).toEqual('RegExp')
})
test('undefined', () => {
expect(type(undefined)).toEqual('Undefined')
})
test('not a number', () => {
expect(type(Number('s'))).toBe('NaN')
})
test('function inside object 1', () => {
const obj = {
f(){
return 4
},
}
expect(type(obj.f)).toBe('Function')
expect(ramdaType(obj.f)).toBe('Function')
})
test('function inside object 2', () => {
const name = 'f'
const obj = {
[ name ](){
return 4
},
}
expect(type(obj.f)).toBe('Function')
expect(ramdaType(obj.f)).toBe('Function')
})
union<T>(x: T[], y: T[]): T[]
It takes two lists and return a new list containing a merger of both list with removed duplicates.
R.equals is used to compare for duplication.
const result = R.union([1,2,3], [3,4,5]);
// => [1, 2, 3, 4, 5]
Try this R.union example in Rambda REPL
import { includes } from './includes'
export function union(x, y){
if (arguments.length === 1) return _y => union(x, _y)
const toReturn = x.slice()
y.forEach(yInstance => {
if (!includes(yInstance, x)) toReturn.push(yInstance)
})
return toReturn
}
import { union } from './union'
test('happy', () => {
expect(union([ 1, 2 ], [ 2, 3 ])).toEqual([ 1, 2, 3 ])
})
test('with list of objects', () => {
const list1 = [ { a : 1 }, { a : 2 } ]
const list2 = [ { a : 2 }, { a : 3 } ]
const result = union(list1)(list2)
})
uniq<T>(list: T[]): T[]
It returns a new array containing only one copy of each element of list.
R.equals is used to determine equality.
const list = [1, 1, {a: 1}, {a: 2}, {a:1}]
R.uniq(list)
// => [1, {a: 1}, {a: 2}]
Try this R.uniq example in Rambda REPL
import { includes } from './includes'
export function uniq(list){
let index = -1
const willReturn = []
while (++index < list.length){
const value = list[ index ]
if (!includes(value, willReturn)){
willReturn.push(value)
}
}
return willReturn
}
import {uniq} from './uniq'
test('happy', () => {
const list = [1, 2, 3, 3, 3, 1, 2, 0]
expect(uniq(list)).toEqual([1, 2, 3, 0])
})
test('with object', () => {
const list = [{a: 1}, {a: 2}, {a: 1}]
expect(uniq(list)).toEqual([{a: 1}, {a: 2}])
})
test('with nested array', () => {
expect(uniq([[42], [42]])).toEqual([[42]])
})
test('with falsy values', () => {
expect(uniq([undefined, null])).toEqual([undefined, null])
})
test('can distinct between string and number', () => {
expect(uniq([1, '1'])).toEqual([1, '1'])
})
uniqWith<T, U>(predicate: (x: T, y: T) => boolean, list: T[]): T[]
It returns a new array containing only one copy of each element in list according to predicate function.
This predicate should return true, if two elements are equal.
const list = [
{id: 0, title:'foo'},
{id: 1, title:'bar'},
{id: 2, title:'baz'},
{id: 3, title:'foo'},
{id: 4, title:'bar'},
]
const expected = [
{id: 0, title:'foo'},
{id: 1, title:'bar'},
{id: 2, title:'baz'},
]
const predicate = (x,y) => x.title === y.title
const result = R.uniqWith(predicate, list)
// => `result` is equal to `expected`
Try this R.uniqWith example in Rambda REPL
import { any } from './any'
export function uniqWith(predicate, list){
if (arguments.length === 1) return _list => uniqWith(predicate, _list)
let index = -1
const willReturn = []
while (++index < list.length){
const value = list[ index ]
const flag = any(x => predicate(value, x),
willReturn)
if (!flag){
willReturn.push(value)
}
}
return willReturn
}
import { uniqWith } from './uniqWith'
const list = [
{a: 1},
{a: 1},
]
test('happy', () => {
const fn = (x, y) => x.a === y.a
const result = uniqWith(fn, list)
expect(result).toEqual([{a:1}])
})
test('curried', () => {
const fn = (x, y) => x.a === y.a
const result = uniqWith(fn)(list)
expect(result).toEqual([{a:1}])
})
unless<T, U>(predicate: (x: T) => boolean, whenFalseFn: (x: T) => U, obj: T): U
The method returns function that will be called with argument input.
If predicate(input) returns false, then the end result will be the outcome of whenFalse(input).
In the other case, the final output will be the input itself.
const fn = R.unless(
x => x > 2,
x => x + 10
)
const result = [
fn(1),
fn(5)
]
// => [11, 5]
Try this R.unless example in Rambda REPL
export function unless(predicate, whenFalse){
if (arguments.length === 1){
return _whenFalse => unless(predicate, _whenFalse)
}
return input => predicate(input) ? input : whenFalse(input)
}
import { inc } from './inc'
import { isNil } from './isNil'
import { unless } from './unless'
test('happy', () => {
const safeInc = unless(isNil, inc)
expect(safeInc(null)).toBeNull()
expect(safeInc(1)).toBe(2)
})
test('curried', () => {
const safeIncCurried = unless(isNil)(inc)
expect(safeIncCurried(null)).toBeNull()
})
update<T>(index: number, newValue: T, list: T[]): T[]
It returns a copy of list with updated element at index with newValue.
const index = 2
const newValue = 88
const list = [1, 2, 3, 4, 5]
const result = R.update(index, newValue, list)
// => [1, 2, 88, 4, 5]
Try this R.update example in Rambda REPL
import { curry } from './curry'
function updateFn(
index, newValue, list
){
const arrClone = list.slice()
return arrClone.fill(
newValue, index, index + 1
)
}
export const update = curry(updateFn)
import { update } from './update'
const list = [ 1, 2, 3 ]
test('happy', () => {
const newValue = 8
const index = 1
const result = update(
index, newValue, list
)
const curriedResult = update(index, newValue)(list)
const tripleCurriedResult = update(index)(newValue)(list)
const expected = [ 1, 8, 3 ]
expect(result).toEqual(expected)
expect(curriedResult).toEqual(expected)
expect(tripleCurriedResult).toEqual(expected)
})
test('list has no such index', () => {
const newValue = 8
const index = 10
const result = update(
index, newValue, list
)
expect(result).toEqual(list)
})
updateObject<Output>(rules: ([string, any])[], input: object): Output
Very similar to R.assocPath but it applies list of updates instead of only a single update.
It return a copy of obj input with changed properties according to rules input.
Each instance of rules is a tuple of object path and the new value for this path. If such object path does not exist, then such object path is created.
As it uses R.path underneath, object path can be either string or array of strings(in Typescript object path can be only a string).
const obj = {
a: {b: 1},
foo: {bar: 10},
}
const rules = [
['a.b', 2],
['foo.bar', 20],
['q.z', 300],
]
const result = R.updateObject(rules, obj)
const expected = {
a: {b: 2},
foo: {bar: 20},
q: {z: 300},
}
// => `result` is equal to `expected`
Try this R.updateObject example in Rambda REPL
import { assocPath } from './assocPath'
export function updateObject(rules, obj){
if (arguments.length === 1) return _obj => updateObject(rules, _obj)
let clone = { ...obj } /*?.*/
rules.forEach(([ objectPath, newValue ]) => {
clone = assocPath(
objectPath, newValue, clone
)
})
return clone
}
import { updateObject } from './updateObject'
const obj = {
a : { b : 1 },
foo : { bar : 10 },
}
const rules = [
[ 'a.b', 2 ],
[ 'foo.bar', 20 ],
[ 'q.z', 300 ],
]
const expected = {
a : { b : 2 },
foo : { bar : 20 },
q : { z : 300 },
}
test('happy', () => {
const result = updateObject(rules, obj)
expect(result).toEqual(expected)
})
test('curried', () => {
const result = updateObject(rules)(obj)
expect(result).toEqual(expected)
})
values<T extends object, K extends keyof T>(obj: T): T[K][]
With correct input, this is nothing more than Object.values(obj). If obj is not an object, then it returns an empty array.
const obj = {a:1, b:2}
R.values(obj)
// => [1, 2]
Try this R.values example in Rambda REPL
import { type } from './type'
export function values(obj){
if (type(obj) !== 'Object') return []
return Object.values(obj)
}
import { values } from './values'
test('happy', () => {
expect(values({
a : 1,
b : 2,
c : 3,
})).toEqual([ 1, 2, 3 ])
})
test('with bad input', () => {
expect(values(null)).toEqual([])
expect(values(undefined)).toEqual([])
expect(values(55)).toEqual([])
expect(values('foo')).toEqual([])
expect(values(true)).toEqual([])
expect(values(false)).toEqual([])
expect(values(NaN)).toEqual([])
expect(values(Infinity)).toEqual([])
expect(values([])).toEqual([])
})
view<T, U>(lens: Lens): (target: T) => U
It returns the value of lens focus over target object.
const lens = R.lensProp('x')
R.view(lens, {x: 1, y: 2}) // => 1
R.view(lens, {x: 4, y: 2}) // => 4
Try this R.view example in Rambda REPL
const Const = x => ({
x,
map : fn => Const(x),
})
export function view(lens, target){
if (arguments.length === 1) return _target => view(lens, _target)
return lens(Const)(target).x
}
import { assoc } from './assoc'
import { lens } from './lens'
import { prop } from './prop'
import { view } from './view'
const testObject = { foo : 'Led Zeppelin' }
const assocLens = lens(prop('foo'), assoc('foo'))
test('happy', () => {
expect(view(assocLens, testObject)).toEqual('Led Zeppelin')
})
viewOr<Input, Output>(fallback: Output, lens: Lens, input: Input): Output
A combination between R.defaultTo and `R.view.
const lens = R.lensProp('a');
const input = {a: 'foo'}
const fallbackInput = {b: 'bar'}
const fallback = 'FALLBACK'
const result = [
R.viewOr(fallback, lens, input),
R.viewOr(fallback, lens, fallbackInput)
]
// => ['foo', 'FALLBACK']
Try this R.viewOr example in Rambda REPL
import { curry } from './curry'
import { defaultTo } from './defaultTo'
import { view } from './view'
function viewOrFn(
fallback, lens, input
){
return defaultTo(fallback, view(lens, input))
}
export const viewOr = curry(viewOrFn)
import { lensProp } from './lensProp'
import { viewOr } from './viewOr'
const lens = lensProp('a')
const input = { a : 'foo' }
const fallbackInput = { b : 'bar' }
const fallback = 'FALLBACK'
test('happy', () => {
const result = viewOr(
fallback, lens, fallbackInput
)
expect(result).toBe(fallback)
})
test('curried', () => {
const result = viewOr(fallback, lens)(input)
expect(result).toBe('foo')
})
wait<T>(fn: Promise<T>): Promise<[T, Error|undefined]>
It provides Golang-like interface for handling promises.
const [result, err] = await R.wait(R.delay(1000))
// => err is undefined
// => result is `RAMBDAX_DELAY`
Try this R.wait example in Rambda REPL
export function wait(fn){
return new Promise(resolve => {
fn.then(result => resolve([ result, undefined ])).catch(e =>
resolve([ undefined, e ]))
})
}
import { wait } from './wait'
test('happy path', async () => {
const fn = x => Promise.resolve(x + 1)
const [ result, err ] = await wait(fn(1))
expect(result).toBe(2)
expect(err).toBeUndefined()
})
test('when promise is rejected', async () => {
const fn = x => Promise.reject(Error('foo'))
const [ result, err ] = await wait(fn(1))
expect(result).toBeUndefined()
expect(err).toEqual(Error('foo'))
})
waitFor(
waitForTrueCondition: () => boolean,
howLong: number,
loops?: number
): () => Promise<boolean>
It returns true, if condition returns true within howLong milisececonds time period.
The method accepts an optional third argument loops(default to 10), which is the number of times waitForTrueCondition will be evaluated for howLong period. Once this function returns a value different from false, this value will be the final result.
Otherwise, R.waitFor will return false.
const howLong = 1000
let counter = 0
const waitForTrueCondition = async x => {
await R.delay(100)
counter = counter + x
return counter > 10
}
const result = await R.waitFor(waitForTrueCondition, howLong)(2)
// => true
Try this R.waitFor example in Rambda REPL
import { delay } from './delay'
import { range } from './range'
import { type } from './type'
export function waitFor(
condition, howLong, loops = 10
){
const typeCondition = type(condition)
const passPromise = typeCondition === 'Async'
const passFunction = typeCondition === 'Function'
const interval = Math.floor(howLong / loops)
if (!(passPromise || passFunction)){
throw new Error('R.waitFor')
}
return async (...inputs) => {
for (const _ of range(0, loops)){
const resultCondition = await condition(...inputs)
if (resultCondition === false){
await delay(interval)
} else {
return resultCondition
}
}
return false
}
}
import { delay } from './delay'
import { waitFor } from './waitFor'
const howLong = 1000
test('true', async () => {
let counter = 0
const condition = x => {
counter++
return counter > x
}
const result = await waitFor(condition, howLong)(6)
expect(result).toEqual(true)
})
test('false', async () => {
let counter = 0
const condition = x => {
counter++
return counter > x
}
const result = await waitFor(condition, howLong)(12)
expect(result).toEqual(false)
})
test('async condition | true', async () => {
let counter = 0
const condition = async x => {
counter++
await delay(10)
return counter > x
}
const result = await waitFor(condition, howLong)(6)
expect(result).toEqual(true)
})
test('async condition | false', async () => {
let counter = 0
const condition = async x => {
counter++
await delay(10)
return counter > x
}
const result = await waitFor(condition, howLong)(12)
expect(result).toEqual(false)
})
test('throws when fn is not function', () => {
const fn = 'foo'
expect(() => waitFor(fn, howLong)()).toThrowWithMessage(Error, 'R.waitFor')
})
when<T, U>(predicate: (x: T) => boolean, whenTrueFn: (a: T) => U, input: T): T | U
import { curry } from './curry'
function whenFn(
predicate, whenTrueFn, input
){
if (!predicate(input)) return input
return whenTrueFn(input)
}
export const when = curry(whenFn)
import { add } from './add'
import { when } from './when'
const predicate = x => typeof x === 'number'
test('happy', () => {
const fn = when(predicate, add(11))
expect(fn(11)).toBe(22)
expect(fn('foo')).toBe('foo')
})
where<T, U>(conditions: T, input: U): boolean
It returns true if all each property in conditions returns true when applied to corresponding property in input object.
R.equals is used to determine equality.
const condition = R.where({
a : x => typeof x === "string",
b : x => x === 4
})
const input = {
a : "foo",
b : 4,
c : 11,
}
const result = condition(input)
// => true
Try this R.where example in Rambda REPL
export function where(conditions, input){
if (input === undefined){
return _input => where(conditions, _input)
}
let flag = true
for (const prop in conditions){
const result = conditions[ prop ](input[ prop ])
if (flag && result === false){
flag = false
}
}
return flag
}
import { equals } from './equals'
import { where } from './where'
test('when true', () => {
const predicate = where({
a : equals('foo'),
b : equals('bar'),
})
expect(predicate({
a : 'foo',
b : 'bar',
x : 11,
y : 19,
})).toEqual(true)
})
test('when false', () => {
const predicate = where({
a : equals('foo'),
b : equals('baz'),
})
expect(predicate({
a : 'foo',
b : 'bar',
x : 11,
y : 19,
})).toEqual(false)
})
whereEq<T, U>(condition: T, input: U): boolean
It will return true if all of input object fully or partially include rule object.
R.equals is used to determine equality.
const condition = { a : { b : 1 } }
const input = {
a : { b : 1 },
c : 2
}
const result = whereEq(condition, input)
// => true
Try this R.whereEq example in Rambda REPL
import { equals } from './equals'
import { filter } from './filter'
export function whereEq(condition, input){
if (arguments.length === 1){
return _input => whereEq(condition, _input)
}
const result = filter((conditionValue, conditionProp) =>
equals(conditionValue, input[ conditionProp ]),
condition)
return Object.keys(result).length === Object.keys(condition).length
}
import { whereEq } from './whereEq'
test('when true', () => {
const condition = { a : 1 }
const input = {
a : 1,
b : 2,
}
const result = whereEq(condition, input)
const expectedResult = true
expect(result).toEqual(expectedResult)
})
test('when false', () => {
const condition = { a : 1 }
const input = { b : 2 }
const result = whereEq(condition, input)
const expectedResult = false
expect(result).toEqual(expectedResult)
})
test('with nested object', () => {
const condition = { a : { b : 1 } }
const input = {
a : { b : 1 },
c : 2,
}
const result = whereEq(condition)(input)
const expectedResult = true
expect(result).toEqual(expectedResult)
})
test('with wrong input', () => {
const condition = { a : { b : 1 } }
expect(() => whereEq(condition, null)).toThrowWithMessage(TypeError,
'Cannot read property \'a\' of null')
})
without<T>(matchAgainst: T[], source: T[]): T[]
It will return a new array, based on all members of source list that are not part of matchAgainst list.
R.equals is used to determine equality.
const source = [1, 2, 3, 4]
const matchAgainst = [2, 3]
const result = R.without(matchAgainst, source)
// => [1, 4]
Try this R.without example in Rambda REPL
import { includesArray } from './includes'
import { reduce } from './reduce'
export function without(matchAgainst, source){
if (source === undefined){
return _source => without(matchAgainst, _source)
}
return reduce(
(prev, current) =>
includesArray(current, matchAgainst) ? prev : prev.concat(current),
[],
source
)
}
import { without } from './without'
test('should return a new list without values in the first argument ', () => {
const itemsToOmit = [ 'A', 'B', 'C' ]
const collection = [ 'A', 'B', 'C', 'D', 'E', 'F' ]
expect(without(itemsToOmit, collection)).toEqual([ 'D', 'E', 'F' ])
expect(without(itemsToOmit)(collection)).toEqual([ 'D', 'E', 'F' ])
})
test('ramda bug', () => {
expect(
without("0:1", ["0", "0:1"])
).toEqual(['0:1'])
})
test('ramda test', () => {
expect(without([ 1, 2 ])([ 1, 2, 1, 3, 4 ])).toEqual([ 3, 4 ])
})
xnor(x: boolean, y: boolean): boolean
Logical XNOR
const result = [
R.xnor(1, 0),
R.xnor(0, 1),
R.xnor(0, 0),
R.xnor(1, 1),
]
// => [true, false, false, true]
Try this R.xnor example in Rambda REPL
export function xnor(x, y){
if (arguments.length === 1){
return _y => xnor(x, _y)
}
return Boolean(x && y || !x && !y)
}
import { xnor } from './xnor'
test('when true', () => {
expect(xnor(1, 1)).toBeTrue()
expect(xnor(0)(0)).toBeTrue()
})
test('when false', () => {
expect(xnor(0, 1)).toBeFalse()
})
xor(x: boolean, y: boolean): boolean
Logical XOR
const result = [
xor(true, true),
xor(false, false),
xor(false, true),
]
// => [false, false, true]
Try this R.xor example in Rambda REPL
export function xor(a, b){
if (arguments.length === 1) return _b => xor(a, _b)
return Boolean(a) && !b || Boolean(b) && !a
}
import { xor } from './xor'
test('compares two values with exclusive or', () => {
expect(xor(true, true)).toEqual(false)
expect(xor(true, false)).toEqual(true)
expect(xor(false, true)).toEqual(true)
expect(xor(false, false)).toEqual(false)
})
test('when both values are truthy, it should return false', () => {
expect(xor(true, 'foo')).toEqual(false)
expect(xor(42, true)).toEqual(false)
expect(xor('foo', 42)).toEqual(false)
expect(xor({}, true)).toEqual(false)
expect(xor(true, [])).toEqual(false)
expect(xor([], {})).toEqual(false)
expect(xor(new Date(), true)).toEqual(false)
expect(xor(true, Infinity)).toEqual(false)
expect(xor(Infinity, new Date())).toEqual(false)
})
test('when both values are falsy, it should return false', () => {
expect(xor(null, false)).toEqual(false)
expect(xor(false, undefined)).toEqual(false)
expect(xor(undefined, null)).toEqual(false)
expect(xor(0, false)).toEqual(false)
expect(xor(false, NaN)).toEqual(false)
expect(xor(NaN, 0)).toEqual(false)
expect(xor('', false)).toEqual(false)
})
test('when one argument is truthy and the other is falsy, it should return true', () => {
expect(xor('foo', null)).toEqual(true)
expect(xor(null, 'foo')).toEqual(true)
expect(xor(undefined, 42)).toEqual(true)
expect(xor(42, undefined)).toEqual(true)
expect(xor(Infinity, NaN)).toEqual(true)
expect(xor(NaN, Infinity)).toEqual(true)
expect(xor({}, '')).toEqual(true)
expect(xor('', {})).toEqual(true)
expect(xor(new Date(), 0)).toEqual(true)
expect(xor(0, new Date())).toEqual(true)
expect(xor([], null)).toEqual(true)
expect(xor(undefined, [])).toEqual(true)
})
zip<K, V>(x: K[], y: V[]): KeyValuePair<K, V>[]
It will return a new array containing tuples of equally positions items from both x and y lists.
The returned list will be truncated to match the length of the shortest supplied list.
const x = [1, 2]
const y = ['A', 'B']
R.zip(x, y)
// => [[1, 'A'], [2, 'B']]
// truncates to shortest list
R.zip([...x, 3], ['A', 'B'])
// => [[1, 'A'], [2, 'B']]
Try this R.zip example in Rambda REPL
export function zip(left, right){
if (arguments.length === 1) return _right => zip(left, _right)
const result = []
const length = Math.min(left.length, right.length)
for (let i = 0; i < length; i++){
result[ i ] = [ left[ i ], right[ i ] ]
}
return result
}
import { zip } from './zip'
const array1 = [ 1, 2, 3 ]
const array2 = [ 'A', 'B', 'C' ]
test('should return an array', () => {
const actual = zip(array1)(array2)
expect(actual).toBeInstanceOf(Array)
})
test('should return and array or tuples', () => {
const expected = [
[ 1, 'A' ],
[ 2, 'B' ],
[ 3, 'C' ],
]
const actual = zip(array1, array2)
expect(actual).toEqual(expected)
})
test('should truncate result to length of shorted input list', () => {
const expectedA = [
[ 1, 'A' ],
[ 2, 'B' ],
]
const actualA = zip([ 1, 2 ], array2)
expect(actualA).toEqual(expectedA)
const expectedB = [
[ 1, 'A' ],
[ 2, 'B' ],
]
const actualB = zip(array1, [ 'A', 'B' ])
expect(actualB).toEqual(expectedB)
})
zipObj<T, K extends string>(keys: K[], values: T[]): { [P in K]: T }
It will return a new object with keys of keys array and values of values array.
const keys = ['a', 'b', 'c']
R.zipObj(keys, [1, 2, 3])
// => {a: 1, b: 2, c: 3}
// truncates to shortest list
R.zipObj(keys, [1, 2])
// => {a: 1, b: 2}
Try this R.zipObj example in Rambda REPL
import { take } from './take'
export function zipObj(keys, values){
if (arguments.length === 1) return yHolder => zipObj(keys, yHolder)
return take(values.length, keys).reduce((
prev, xInstance, i
) => {
prev[ xInstance ] = values[ i ]
return prev
}, {})
}
import { equals } from './equals'
import { zipObj } from './zipObj'
test('zipObj', () => {
expect(zipObj([ 'a', 'b', 'c' ], [ 1, 2, 3 ])).toEqual({
a : 1,
b : 2,
c : 3,
})
})
test('0', () => {
expect(zipObj([ 'a', 'b' ])([ 1, 2, 3 ])).toEqual({
a : 1,
b : 2,
})
})
test('1', () => {
expect(zipObj([ 'a', 'b', 'c' ])([ 1, 2 ])).toEqual({
a : 1,
b : 2,
})
})
test('ignore extra keys', () => {
const result = zipObj([ 'a', 'b', 'c', 'd', 'e', 'f' ], [ 1, 2, 3 ])
const expected = {
a : 1,
b : 2,
c : 3,
}
expect(equals(result, expected)).toBeTrue()
})
zipWith<T, U, TResult>(fn: (x: T, y: U) => TResult, list1: T[], list2: U[]): TResult[]
const list1 = [ 10, 20, 30, 40 ]
const list2 = [ 100, 200 ]
const result = R.zipWith(
R.add, list1, list2
)
// => [110, 220]
Try this R.zipWith example in Rambda REPL
import { curry } from './curry'
import { take } from './take'
function zipWithFn(
fn, x, y
){
return take(x.length > y.length ? y.length : x.length,
x).map((xInstance, i) => fn(xInstance, y[ i ]))
}
export const zipWith = curry(zipWithFn)
import { add } from './add'
import { zipWith } from './zipWith'
const list1 = [ 1, 2, 3 ]
const list2 = [ 10, 20, 30, 40 ]
const list3 = [ 100, 200 ]
test('when second list is shorter', () => {
const result = zipWith(
add, list1, list3
)
expect(result).toEqual([ 101, 202 ])
})
test('when second list is longer', () => {
const result = zipWith(
add, list1, list2
)
expect(result).toEqual([ 11, 22, 33 ])
})
7.4.0
Add R.objOf method
Add R.mapObjIndexed method
7.3.0
Add R.rejectIndexed and R.partitionIndexed methods - Rambdax issue #67
Expose R.mapObject, R.mapArray, R.filterObject and R.filterArray - Issue #578
R.has use Object.prototype.hasOwnProperty- Issue #572
Fix R.intersection wrong order compared to Ramda.
Expose immutable.ts typings which are Rambda typings with readonly statements - Issue #565, Rambdax issue #69
R.path wrong return of null instead of undefined when path value is null - PR #577
Wrong arguments order in R.removeIndex - Issue #66
Change R.piped typings to mimic that of R.pipe. Main difference is that R.pipe is focused on unary functions.
Fix wrong logic when R.without use R.includes while it should use array version of R.includes.
Use uglify plugin for UMD bundle.
Remove ts-toolbelt types from Typescript definitions. Most affected are the following methods, which lose one of its curried definitions:
7.2.0
Approve PR #61 - fix wrong R.isValid typings
R.produceAsync returns promise even if all rules are synchronous.
R.defaultTo no longer accepts infinite inputs, thus it follows Ramda implementation.
R.equals supports equality of functions.
R.pipe doesn't use R.compose.
Close Issue #561 - export several internal TS interfaces and types
Add CHANGELOG.md file in release files list
7.1.0
Add R.tryCatchAsync
Add R.xnor
R.equals supports equality of functions.
Close Issue #559 - improve R.propOr typings
Close Issue #560 - apply immutable lint to Typescript definitions
Close Issue #553 - fix problem with curried typings of R.prop
Fix wrong R.last typing
Upgrade all rollup related dependencies
R.type supports Symbol just like Ramda.
Remove file extension in main property in package.json in order to allow experimental-modules. See also this Ramda's PR - https://github.com/ramda/ramda/pull/2678/files
Import R.indexBy/R.when/R.zipObj/R.propEq/R.complement changes from recent @types/ramda release.
R.tryCatch stop supporting asynchronous functions; the previous behaviour is exported to Rambdax as R.tryCatchAsync
7.0.1
Evolved declaration in Typescript definition7.0.0
Rename R.produce to R.produceAsync
Add R.produce which is synchronous version of R.produceAsync
Stop supporting expression inside template's props. Also, spaces are no longer allowed between {{ and }}, i.e. R.interpolate('{{ foo }}', x) should be R.interpolate('{{foo}}', x).
Add typings for R.takeWhile when iterable is a string
Add R.takeLastWhile
Add R.dropWhile
Add R.eqProps
Add R.dropLastWhile
Add R.dropRepeats
Add R.dropRepeatsWith
Add R.evolve
6.2.0
R.switcher accepts undefined as valid input
Add R.props
Add R.zipWith
Add R.splitAt
Add R.splitWhen
Close Issue #547 - restore readonly declaration in Rambda Typescript definitions.
R.append/R.prepend now work only with arrays just like Ramda. Previous behaviour was for them to work with both arrays and strings.
Sync R.pluck typings with @types/ramda as there was a tiny difference.
6.1.0
Add R.mapIndexed
Add R.filterIndexed
Add R.forEachIndexed
Fix R.and wrong definition, because the function doesn't convert the result to boolean. This introduce another difference with @types/ramda.
Add R.once
Add R.or
6.0.0
Breaking change - R.map/R.filter/R.reject/R.forEach/R.partition doesn't pass index as second argument to the predicate, when looping over arrays. The old behaviour of map, filter and forEach can be found in Rambdax methods R.mapIndexed, R.filterIndexed and R.forEachIndexed(introduced in version 6.1.0).
Breaking change - R.all/R.none/R.any/R.find/R.findLast/R.findIndex/R.findLastIndex doesn't pass index as second argument to the predicate.
Add R.applyDiff method
Change R.assocPath typings so the user can explicitly sets type of the new object
Typings of R.assoc match its @types/ramda counterpart.
Simplify R.forEach typings
Remove ReadonlyArray<T> pattern from Typescript definitions - not enough value for the noise it adds.
Fix typing of R.reject as it wrongly declares that with object, it pass property to predicate.
5.1.0
Add R.takeUntil method
Fix wrong R.takeWhile
5.0.0
Deprecate R.change method - it does too much; partially replaced with R.updateObject.
Deprecate R.compact method - vague use case; R.filter does the same job.
R.produce always returns a promise
Add R.updateObject method
Add R.takeWhile method
Add R.viewOr method
Add R.pipeAsync method
Add R.removeIndex method
Add R.excludes method
R.includes throws on wrong input, i.e. R.includes(1, null)
Close Issue #524 - R.assocPath wrong logic when number is used in array path input.
R.mapToObjectAsync supports currying
R.mapAsyncLimit supports currying
Fix R.mapAsync to pass property to iterator, when input is an object.
Fix currying for several async methods - R.tapAsync, R.produce, R.filterAsync *(extend typings)
4.2.0
Add R.move method
Add R.union method
Add R.lensSatisfies method
Add R.mapKeys method
Add R.sortByPath method
Add R.sortByProps method
Close Issue #519 -
ts-toolbelt needs other type of export with --isolatedModules flag
4.1.0
R.template is renamed to R.interpolate
R.equals now supports negative zero just like Ramda.equals
Add R.replaceAll method
Add R.lensEq method
4.0.1
Forgot to export R.of because of wrong marker in files/index.d.ts
4.0.0
Deprecate the following methods:
R.promiseAllObject - because R.produce serves the same purposeR.composed - because R.piped makes more sense, when we want to pass the input at the start of the functionR.defaultToStrict - confusing logicR.findInObject - overestimated importanceR.headObject - overestimated importanceR.includesType - overestimated importanceR.inject - confusing logicR.isAttach - confusing logicR.mergeRight - overestimated importanceR.opposite - overestimated importanceR.otherwise - overestimated importanceR.pushUniq - overestimated importanceR.resolve - overestimated importanceR.s - overestimated importanceR.toggle - overestimated importanceR.uuid - not suitableR.whenAsync - overestimated importanceMove the following methods to Rambda and change their logic to match Ramda implementation:
R.hasPathR.unlessR.pathEqR.tryCatchR.whereR.whereEqAlso these changes:
R.flatMap - renamed to R.chain and moved to Rambda
R.ifElseAsync - accept any number of arguments for the returned function
R.produce, R.filterAsync, R.debounce, R.throttle - fix typings
R.mapAsyncLimit - drop support for curring and therefore for usage with R.composeAsync
Improve R.ok throwed error message
R.ok returns undefined instead of true when validation passes.
R.mergeDeep is renamed to R.mergeDeepLeft
Add R.pipeAsync
Take R.partialCurry from Rambda as it is deprecated there
3.7.0
Sync with Rambda
Add R.lens
Add R.lensIndex
Add R.lensPath
Add R.lensProp
Add R.over
Add R.set
Add R.view
Add R.paths
Add R.xor
Add R.cond
3.6.0
Add R.mapAsyncLimit
Add R.toggle, match Ramda upcoming method specification
Add R.isValidAsync
Extend R.template without introducing breaking change
3.5.0 Sync with Rambda - add methods descriptions to Typescript definitions
3.4.0 Sync with Rambda and close Issue #42
3.3.0 Fix R.sortObject typing
3.3.0 Add R.filterAsync and R.sortObject methods
3.2.0 R.uuid accept second argument in order to return string only uuid
3.1.0 Dynamic set of exports lead to adding previously ommited Rambda exports such as R.identical
3.0.3 Sync with Rambda - new functionality of R.isEmpty
3.0.2 Add typings for R.mapToObject
3.0.1 Fix typings
3.0.0 Breaking change as Rambda also has breaking changes
Read more about it in Rambda changelog
Also with this versions, typings tests are provided and several definitions are changed.
R.anyTrue, R.anyFalse, R.allTrue, R.allFalse use internal isTruthy and isFalsy methods. Empty array and object with zero length are considered falsy.
Deprecate R.contains
Deprecate R.defaultToWhen
Moved R.runTests to helpers repo
2.17.0 Change in R.runTests logic. It will be removed from Rambdax to helpers repo.
2.16.0 Restore R.runTests but without documentation
getEvaluations, getPositiveEvaluation, getNegativeEvaluation in the context of R.runTests2.15.0 Several changes
Typescript definitions have been updated and typings tests are introduced
R.mapAsync and R.mapFastAsync pass index as second argument
2.14.1 Restore R.contains
2.14.0 Several changes:
R.inject accept before flag as fourth argument
Remove R.includesAny
Improve typing of R.partition
R.nextIndex and R.prevIndex work also with number as second argument
2.13.1 Deprecate R.log and R.runTests
2.12.3 Add 'dist' directory to files
2.12.2 Add R.mapToObject typings
2.12.0 Sync with Rambda
2.11.1 Fix R.waitFor
2.11.0 Add R.toDecimal
2.10.2 Fix issue 32
2.10.0 deprecate R._
2.9.1 R.fromPairs/toPairs typing
2.9.0 npm doesn't update version on their site
2.8.2 R.map typing
2.8.0 Sync with Rambda | no need for create types script
2.7.0 Add R.prevIndex
2.6.2 Sync with Rambda
2.6.0 R.log depends on RAMBDAX_LOG
2.5.0 Rambda's partial
2.4.0 Add R.uuid
2.3.0 R._ parse to constant case
This introduce breaking change for ie11 as noted in issue 31 which is fixed with
2.10.0which deprecates this method
2.2.1 Add R.log, R.logInit and R.logHolder
2.1.0 Add R._
2.0.0 Add R.toggle
1.9.0 Add R.pushUniq
1.8.2 No need for sourcemaps
1.8.1 Fix building with regeneratorRuntime
1.8.0 Upgrade to new major Rollup release
Restore R.headObject
Add R.hasPath method
1.7.2 R.memoize contains dev console.logs
1.7.1 Forgot to build types
1.7.0 Rename R.then to R.resolve because of Ramda issue with R.then(they rename it to R.andThen)
R.isFalsy, R.nextIndex and R.mergeDeep1.6.3 Forgot to export R.unless(credit to @mobily for the PR)
1.6.0 Restore R.compact method
1.5.6 R.maybe accepts also anonymous functions as second and third argument
1.5.5 Add R.maybe method
DeepScan serviceR.then and R.otherwiseR.change increase nesting level to 41.4.1 R.isValid didn't work with Number prototype
1.4.0 Add multiple methods
Add R.defaultToStrict
Add R.defaultToWhen
Add R.whereEq
Add R.partition
Add R.negate is renamed to R.opposite
Add R.then
Add R.otherwise
R.isValid accepts prototypes as rules, i.e. schema = {a: String}
The prevoious point leads to the same change applied to the methods depending on R.isValid, i.e. R.ok, R.pass and R.isAttach
1.3.0 Add R.unless
R.when accepts both function and value for whenTrue argument. The same is valid for R.unless
export R.negate which is the same as R.complement
1.2.0 Export src folder
1.1.0 Restore promiseAllObject and flatMap
1.0.1 Fix typings
1.0.0 Deprecate the following methods:
compact
evolve
flatMap
greater
intersection
less
omitBy
pickBy
promiseAllObject
promiseAllSecure
rangeBy
Also pass deprecation of
addIndexfromRambda@2.0.0
0.24.0 add R.pipedAsync, replace R.multiline with R.glue, remove R.validate
0.23.0 Add R.count
0.22.0 Add R.includesAny
0.21.0 Add R.includesType
0.20.1 R.pass and R.ok work with single schema.
0.20.0 Add R.pathEq
0.19.0 Add R.wait, expose already complete R.waitFor
0.18.0 AddR.anyType and R.allType
0.17.0 Rename R.is to R.pass and restore R.is original functionality.
0.16.0 getter, setter, reset methods
0.15.3 No more prepublish script
0.15.2 curry in remove
Last version with
libfolder exposed
Most influential contributors
@farwayer - improving performance in R.find, R.filter; give the idea how to make benchmarks more reliable;
@thejohnfreeman - add R.assoc, R.chain;
@helmuthdu - add R.clone; help improve code style;
@jpgorman - add R.zip, R.reject, R.without, R.addIndex;
@ku8ar - add R.slice, R.propOr, R.identical, R.propIs and several math related methods; introduce the idea to display missing Ramda methods;
@romgrk - add R.groupBy, R.indexBy, R.findLast, R.findLastIndex;
@squidfunk - add R.assocPath, R.symmetricDifference, R.difference, R.intersperse;
@synthet1c - add all lenses methods; add R.applySpec, R.converge;
@vlad-zhukov - help with configuring Rollup, Babel; change export file to use ES module exports;
Rambda references
Links to Rambda
[https://mailchi.mp/webtoolsweekly/web-tools-280](Web Tools Weekly)
Deprecated from
Used bysection
Rambda since October/2020 commit that removes RambdaReleases
Rambda's releases before 6.4.0 were used mostly for testing purposes.
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Run-fnCLI commands for lint JS/TS files, commit git changes and upgrade of dependencies |
FAQs
Extended version of Rambda - a lightweight, faster alternative to Ramda
The npm package rambdax receives a total of 9,785 weekly downloads. As such, rambdax popularity was classified as popular.
We found that rambdax demonstrated a healthy version release cadence and project activity because the last version was released less than a year ago. It has 1 open source maintainer collaborating on the project.
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