Rambda is a lightweight and fast utility library that provides a variety of functions for functional programming in JavaScript. It is a smaller and faster alternative to Ramda, offering a similar API but with a focus on performance and simplicity.
Currying
Currying is a technique of evaluating functions with multiple arguments, one at a time. Rambda's `curry` function allows you to transform a function so that it can be called with fewer arguments than it expects, returning a new function that takes the remaining arguments.
const R = require('rambda');
const add = R.curry((a, b) => a + b);
const add5 = add(5);
console.log(add5(3)); // 8Composition
Function composition is the process of combining two or more functions to produce a new function. Rambda's `compose` function allows you to create a pipeline of functions that are executed from right to left.
const R = require('rambda');
const add = (a, b) => a + b;
const multiply = (a, b) => a * b;
const addAndMultiply = R.compose(R.multiply(2), R.add(3));
console.log(addAndMultiply(4)); // 14Cloning
Cloning is the process of creating a deep copy of an object. Rambda's `clone` function allows you to create a deep copy of an object, ensuring that changes to the new object do not affect the original object.
const R = require('rambda');
const obj = {a: 1, b: 2};
const clonedObj = R.clone(obj);
console.log(clonedObj); // {a: 1, b: 2}Filtering
Filtering is the process of selecting a subset of items from a collection based on a predicate function. Rambda's `filter` function allows you to filter elements in an array or object based on a provided predicate.
const R = require('rambda');
const isEven = n => n % 2 === 0;
const numbers = [1, 2, 3, 4, 5, 6];
const evenNumbers = R.filter(isEven, numbers);
console.log(evenNumbers); // [2, 4, 6]Mapping
Mapping is the process of transforming each item in a collection using a provided function. Rambda's `map` function allows you to apply a function to each element in an array or object, returning a new array or object with the transformed elements.
const R = require('rambda');
const double = n => n * 2;
const numbers = [1, 2, 3, 4, 5];
const doubledNumbers = R.map(double, numbers);
console.log(doubledNumbers); // [2, 4, 6, 8, 10]Lodash is a popular utility library that provides a wide range of functions for common programming tasks. It is more feature-rich compared to Rambda but also larger in size. Lodash focuses on performance and ease of use, offering a comprehensive set of tools for working with arrays, objects, strings, and more.
Underscore is another utility library that provides a variety of functional programming helpers. It is similar to Lodash but with a smaller footprint and fewer features. Underscore offers a core set of functions for working with collections, arrays, objects, and functions, making it a good choice for projects that need a lightweight utility library.
Ramda is a functional programming library for JavaScript that emphasizes immutability and pure functions. It offers a similar API to Rambda but with a larger set of functions and a focus on functional programming principles. Ramda is more feature-rich but also larger in size compared to Rambda.
Faster alternative to Ramda in just 10kB - Documentation
I admire Ramda, as it is great library in what it does. My main problem was its size. Even custom builds didn't deliver satisfactory results. Also I already had Ramda habits and I didn't want to switch to Lodash.
Then I realized that my best solution was to publish a library that recreates the functionality of some Ramda methods with less code.
const R = require("rambda")
const result = R.compose(
R.join("-"),
R.filter(a => a > 2),
R.flatten,
)([ [1], [2], [3], 4])
console.log(result) // => "3-4"
Use npm i rambda for Webpack and Node.js usage
For browser usage include in your HTML
https://cdnjs.cloudflare.com/ajax/libs/rambda/0.8.0/webVersion.js
Rambda shadows only small part of the Ramda's API.
A few things to note:
Rambda's methods should be compatible with most of the basic Ramda's methods. For more complex and Ramda specific methods(such as R.__), you should expect a mismatch.
Rambda's type detect async functions. The returned value is "Async"
Rambda's type detect unresolved Promises. The returned value is "Promise"
Rambda's map/filter work only for arrays, while Ramda's map/filter accept also objects.
Rambda's equals doesn't protect against circular structures as Ramda.equals does.
Rambda's path, pick and omit accepts both string and array as condition argument.
Rambda's partialCurry and includes are not part of Ramda API.
Rambda is tested for compatability with Ramda.flip, as this method could be useful in some cases.
If you need more Ramda methods in Rambda, you may either submit a
PRor check the extended version of Rambda - Rambdax
add(a: Number, b: Number): Number
R.add(2, 3) //=> 5
addIndex(fn: Function): Function
const mapWithIndex = R.addIndex(R.map)
mapWithIndex(
(val, index) => `${val} - ${index}`,
["A", "B", "C"]
) // => ["A - 0", "B - 1", "C - 2"]
adjust(replaceFn: Function, i:Number, arr:Array): Array
i index in arr with the result of replaceFn(arr[i])R.adjust(a => a + 1, 0, [0, 100]) //=> [1, 100]
any(condition: Function, arr: Array): Boolean
arr returns true, when passed to the condition functionR.any(a => a * a > 8)([1, 2, 3]) //=> true
R.any(a => a * a > 10)([1, 2, 3]) //=> false
append(valueToAppend: any, arr: Array): Array
R.append('foo', ['bar', 'baz']) //=> ['foo', 'bar', 'baz']
compose(fn1: Function, ... , fnN: Function): any
Performs right-to-left function composition
const result = R.compose(
R.map(a => a*2)
R.filter(val => val>2),
)([1, 2, 3, 4])
console.log(result) // => [6, 8]
contains(valueToFind: any, arr: Array): Boolean
Returns true if valueToFind is part of arr
R.contains(2, [1, 2]) //=> true
R.contains(3, [1, 2]) //=> false
curry(fn: Function): Function
Returns curried version of fn
const addFourNumbers = (a, b, c, d) => a + b + c + d
const curriedAddFourNumbers = R.curry(addFourNumbers)
const f = curriedAddFourNumbers(1, 2)
const g = f(3)
g(4) // => 10
defaultTo(defaultArgument: T, inputArgument: any): T
Returns defaultArgument if inputArgument is undefined or the type of inputArgument is different of the type of defaultArgument.
Returns inputArgument in any other case.
R.defaultTo('foo', undefined) //=> 'foo'
R.defaultTo('foo')('bar') //=> 'bar'
R.defaultTo('foo')(1) //=> 'foo'
drop(howManyToDrop: Number, arrOrStr: Array|String): Array|String
Returns arrOrStr with howManyToDrop items dropped from the left
R.drop(1, ['foo', 'bar', 'baz']) //=> ['bar', 'baz']
R.drop(1, 'foo') //=> 'oo'
dropLast(howManyToDrop: Number, arrOrStr: Array|String): Array|String
Returns arrOrStr with howManyToDrop items dropped from the right
R.dropLast(1, ['foo', 'bar', 'baz']) //=> ['foo', 'bar']
R.dropLast(1, 'foo') //=> 'fo'
equals(a: any, b: any): Boolean
a and bDoesn't handles cyclical data structures
R.equals(1, 1) //=> true
R.equals({}, {}) //=> false
R.equals([1, 2, 3], [1, 2, 3]) //=> true
filter(filterFn: Function, arr: Array): Array
Filters arr throw boolean returning filterFn
const filterFn = a => a % 2 === 0
R.filter(filterFn, [1, 2, 3, 4]) //=> [2, 4]
find(findFn: Function, arr: Array): T|undefined
Returns undefined or the first element of arr satisfying findFn
const findFn = a => R.type(a.foo) === "Number"
const arr = [{foo: "bar"}, {foo: 1}]
R.find(findFn, arr) //=> {foo: 1}
findIndex(findFn: Function, arr: Array): Number
Returns -1 or the index of the first element of arr satisfying findFn
const findFn = a => R.type(a.foo) === "Number"
const arr = [{foo: "bar"}, {foo: 1}]
R.find(findFn, arr) //=> 1
flatten(arr: Array): Array
R.flatten([ 1, [ 2, [ 3 ] ] ]
//=> [ 1, 2, 3 ]
has(prop: String, obj: Object): Boolean
true if obj has property propR.has("a", {a: 1}) //=> true
R.has("b", {a: 1}) //=> false
head(arrOrStr: Array|String): any
arrOrStrR.head([1, 2, 3]) //=> 1
R.head('foo') //=> 'f'
ifElse(condition: Function, ifFn: Function, elseFn: Function): Function
It returns a function that, which input argument is passed to condition function returns answer.
If answer is true, then input is applied to ifFn function.
If answer is false, then input is applied to elseFn function.
const fn = R.ifElse(
x => x > 10,
x => x*2,
x => x*10
)
fn(8) // => 80
fn(11) // => 22
indexOf(valueToFind: any, arr: Array): Number
Returns -1 or the index of the first element of arr equal of valueToFind
R.indexOf(1, [1, 2]) //=> 0
init(arrOrStr: Array|String): Array|String
arrOrStrR.init([1, 2, 3]) //=> [1, 2]
R.init('foo') //=> 'fo'
join(separator: String, arr: Array): String
R.join('-', [1, 2, 3]) //=> '1-2-3'
last(arrOrStr: Array|String): any
arrOrStrR.last(['foo', 'bar', 'baz']) //=> 'baz'
R.last('foo') //=> 'o'
length(arrOrStr: Array|String): Number
R.length([1, 2, 3]) //=> 3
map(mapFn: Function, arr: Array): Array
Returns the result of looping through arr with mapFn
const mapFn = x => x * 2;
R.map(mapFn, [1, 2, 3]) //=> [2, 4, 6]
match(regExpression: Regex, str: String): Array
R.match(/([a-z]a)/g, 'bananas') //=> ['ba', 'na', 'na']
merge(a: Object, b: Object)
Returns result of Object.assign({}, a, b)
R.merge({ 'foo': 0, 'bar': 1 }, { 'foo': 7 })
//=> { 'foo': 7, 'bar': 1 }
omit(propsToOmit: Array, obj: Object): Object
obj with omitting propsToOmitR.omit(['a', 'd'], {a: 1, b: 2, c: 3}) //=> {b: 2, c: 3}
path(pathToSearch: Array|String, obj: Object): any
pathToSearch in object objR.path('a.b', {a: {b: 2}}) //=> 2
R.path(['a', 'b'], {a: {b: 2}}) //=> 2
R.path(['a', 'c'], {a: {b: 2}}) //=> undefined
partialCurry(fn: Function|Async, a: Object, b: Object): Function|Promise
When called with function fn and first set of input a, it will return a function.
This function will wait to be called with second set of input b and it will invoke fn with the merged object of a over b.
fn can be asynchronous function. In that case a Promise holding the result of fn is returned.
See the example below:
const fn = ({a, b, c}) => {
return (a * b) + c
}
const curried = R.partialCurry(fn, {a: 2})
curried({b: 3, c: 10}) //=> 16
Note that partialCurry is method specific for Rambda and the method is not part of Ramda's API
You can read my argumentation for creating partialCurry here
pick(propsToPick: Array, obj: Object): Object
obj containing only propsToPick propertiesR.pick(['a', 'c'], {a: 1, b: 2}) //=> {a: 1}
pluck(property: String, arr: Array): Array
property taken from the objects in array of objects arrR.pluck('a')([{a: 1}, {a: 2}, {b: 3}]) //=> [1, 2]
prepend(valueToPrepend: any, arr: Array): Array
R.prepend('foo', ['bar', 'baz']) //=> ['foo', 'bar', 'baz']
prop(propToFind: String, obj: Object): any
Returns undefined or the value of property propToFind in obj
R.prop('x', {x: 100}) //=> 100
R.prop('x', {a: 1}) //=> undefined
propEq(propToFind: String, valueToMatch: any, obj: Object): Boolean
Returns true if obj has property propToFind and its value is equal to valueToMatch
const propToFind = "foo"
const valueToMatch = 0
R.propEq(propToFind, valueToMatch)({foo: 0}) //=> true
R.propEq(propToFind, valueToMatch)({foo: 1}) //=> false
range(start: Number, end: Number): Array
start(inclusive) to end(exclusive)R.range(0, 2) //=> [0, 1]
reduce(iteratorFn: Function, accumulator: any, array: Array): any
iteratorFn and passing it an accumulator value and the current value from the array, and then passing the result to the next call.The iterator function behaves like the native callback of the Array.prototype.reduce method.
const iteratorFn = (acc, val) => acc + val
R.reduce(iteratorFn, 1, [1, 2, 3]) //=> 7
repeat(valueToRepeat: T, num: Number): Array
R.repeat('foo', 2) //=> ['foo', 'foo']
replace(strOrRegex: String|Regex, replacer: String, str: String): String
Replace strOrRegex found in str with replacer
R.replace('foo', 'bar', 'foo foo') //=> 'bar foo'
R.replace(/foo/, 'bar', 'foo foo') //=> 'bar foo'
R.replace(/foo/g, 'bar', 'foo foo') //=> 'bar bar'
sort(sortFn: Function, arr: Array): Array
Returns copy of arr sorted by sortFn
sortFn must return Number
const sortFn = (a, b) => a - b
R.sort(sortFn, [3, 1, 2]) //=> [1, 2, 3]
sortBy(sortFn: Function, arr: Array): Array
Returns copy of arr sorted by sortFn
sortFn must return value for comparison
const sortFn = obj => obj.foo
R.sortBy(sortFn, [
{foo: 1},
{foo: 0}
])
//=> [{foo: 0}, {foo: 1}]
split(separator: String, str: String): Array
R.split('-', 'a-b-c') //=> ['a', 'b', 'c']
splitEvery(sliceLength: Number, arrOrString: Array|String): Array
arrOrStr into slices of sliceLengthR.splitEvery(2, [1, 2, 3]) //=> [[1, 2], [3]]
R.splitEvery(3, 'foobar') //=> ['foo', 'bar']
subtract(a: Number, b: Number): Number
Returns a minus b
R.subtract(3, 1) //=> 2
tail(arrOrStr: Array|String): Array|String
arrOrStrR.tail([1, 2, 3]) //=> [2, 3]
R.tail('foo') //=> 'oo'
take(num: Number, arrOrStr: Array|String): Array|String
num elements of arrOrStrR.take(1, ['foo', 'bar']) //=> ['foo']
R.take(2, ['foo']) //=> 'fo'
takeLast(num: Number, arrOrStr: Array|String): Array|String
num elements of arrOrStrR.takeLast(1, ['foo', 'bar']) //=> ['bar']
R.takeLast(2, ['foo']) //=> 'oo'
test(regExpression: Regex, str: String): Boolean
str matches regExpressionR.test(/^f/, 'foo') //=> true
R.test(/^f/, 'bar') //=> false
toLower(str: String): String
R.toLower('FOO') //=> 'foo'
toUpper(str: String): String
R.toUpper('foo') //=> 'FOO'
trim(str: String): String
R.trim(' foo ') //=> 'foo'
type(a: any): String
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"
const delay = ms => new Promise(resolve => {
setTimeout(function () {
resolve()
}, ms)
})
R.type(delay) //=> "Promise"
uniq(arr: Array): Array
arrR.uniq([1, 1, 2, 1]) //=> [1, 2]
R.uniq([1, '1']) //=> [1, '1']
update(i: Number, replaceValue: any, arr: Array): Array
arr with the element at i index
replaced with replaceValueR.update(0, "foo", ['bar', 'baz']) //=> ['foo', baz]
values(obj: Object): Array
objR.values({a: 1, b: 2}) //=> [1, 2]
I haven't tested it fully, but the partial test shows that Ramda definitions can be used.
You need to replace declare module ramda with declare module rambda on line 10 and store the file as rambda.js in your flow-typed folder
R.ifElseR.not, R.includes | Take string as condition for R.pick and R.omitR.valuesR.omitR.curry, which used to return incorrectly function when called with more argumentses2015; Approve PR #10 - add R.addIndex to the APIPromise support for R.typeR.reduce to the APIcurry to partialCurry; add new method curry, which works just like Ramda's currydocsifyIf you want to add another Ramda method to the API, please feel free to submit a PR .
The only requirement is the new method to have exact or very close implementation compared to the corresponding Ramda method.
I give you example steps of the PR process.
Create a method file in
modulesfolder.
If the new method is R.endsWith, then the created file will be ./modules/endsWith.js
Write the function declaration and function's logic.
function endsWith(x, arrOrStr){
return arrOrStr.endsWith(x)
}
Any method, which takes more than one argument, should be curried.
We can use the standard curring used throughout Rambda.
function endsWith(x, arrOrStr){
if(arrOrStr === undefined){
return arrOrStrHolder => endsWith(x, arrOrStrHolder)
}
return arrOrStr.endsWith(x)
}
module.exports = endsWith
Or we can also use R.curry, but it is not as performant as the example above.
const curry = require('./curry')
function endsWith(x, arrOrStr){
if(arrOrStr === undefined){
return holder => endsWith(x, arrOrStr)
}
return arrOrStr.endsWith(x)
}
module.exports = curry(endsWith)
Edit
rambda.jsfile
Exported methods are sorted alphabetically
exports.dropLast = require("./modules/dropLast")
exports.endsWith = require("./modules/endsWith")
exports.equals = require("./modules/equals")
Write your test cases
Create file endsWith.js in folder __tests__
const R = require('../rambda')
test('endsWith', () => {
expect(R.endsWith('oo')('foo')).toBeTruthy()
})
Run
npm testto validate your tests
Edit
./README.mdto add documentation
Note that your documentation should match the pattern visible across ./README.md
Lint your files
npm run lint modules/endsWith.js
npm run lint __tests__/endsWith.js
Submit PR
Expect response within 2 days.
Projects using Rambda
Articles about Rambda
FAQs
Lightweight and faster alternative to Ramda with included TS definitions
The npm package rambda receives a total of 551,776 weekly downloads. As such, rambda popularity was classified as popular.
We found that rambda demonstrated a healthy version release cadence and project activity because the last version was released less than a year ago. It has 0 open source maintainers collaborating on the project.
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