rambda

What is rambda?

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.

What are rambda's main functionalities?

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)); // 8

Composition

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)); // 14

Cloning

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]

Other packages similar to rambda

lodash

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

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

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.

README

Rambda

Faster alternative to Ramda in just 6kB

Argumentation

I admire Ramda as it is great library in what it does, but I used only small part of what it offers.

I wanted to optimize the size of my bundle, but already developed Ramda habits.

This lead me to the idea to recreate the funtionality of some Ramda methods and export that as library.

Example use

// npm i rambda
const R = require("rambda")
const result = R.compose(
  R.filter(val => val>2),
  R.flatten,
)([ [1], [2], [3], 4])
console.log(result) // => [3,4]

Differences between Rambda and Ramda

Rambda shadows only small part of the Ramda's API. A few things to note:

• Rambda's methods are not compatible with the placeholder Ramda.__.

In some cases Ramda.__ can be replaced by Ramda.flip. Rambda is tested for compatability with Ramda.flip.

• Rambda's equals doesn't protect against circular structures as Ramda.equals does

Benchmark

Disclaimer

• Documentation of the methods below is scraped from Ramda's website and could be removed in the future, if requested from Ramda's side.

API

add

• Adds two values.

R.add(2, 3);       //=>  5
R.add(7)(10);      //=> 17

adjust

• Applies a function to the value at the given index of an array, returning a new copy of the array with the element at the given index replaced with the result of the function application.

R.adjust(R.add(10), 1, [0, 1, 2]);     //=> [0, 11, 2]
R.adjust(R.add(10))(1)([0, 1, 2]);     //=> [0, 11, 2]

any

• Returns true if at least one of elements of the list match the predicate, false otherwise. Dispatches to the any method of the second argument, if present. Acts as a transducer if a transformer is given in list position.

var lessThan0 = R.flip(R.lt)(0);
var lessThan2 = R.flip(R.lt)(2);
R.any(lessThan0)([1, 2]); //=> false
R.any(lessThan2)([1, 2]); //=> true

append

• Returns a new list containing the contents of the given list, followed by the given element.

R.append('tests', ['write', 'more']); //=> ['write', 'more', 'tests']
R.append('tests', []); //=> ['tests']
R.append(['tests'], ['write', 'more']); //=> ['write', 'more', ['tests']]

contains

• Returns true if the specified value is equal, in R.equals terms, to at least one element of the given list; false otherwise.

R.contains(3, [1, 2, 3]); //=> true
R.contains(4, [1, 2, 3]); //=> false
R.contains([42], [[42]]); //=> true

drop

• Returns all but the first n elements of the given list, string, or transducer/transformer (or object with a drop method). Dispatches to the drop method of the second argument, if present.

R.drop(1, ['foo', 'bar', 'baz']); //=> ['bar', 'baz']
R.drop(2, ['foo', 'bar', 'baz']); //=> ['baz']
R.drop(3, ['foo', 'bar', 'baz']); //=> []
R.drop(4, ['foo', 'bar', 'baz']); //=> []
R.drop(3, 'ramda');               //=> 'da'

dropLast

• Returns a list containing all but the last n elements of the given list.

R.dropLast(1, ['foo', 'bar', 'baz']); //=> ['foo', 'bar']
R.dropLast(2, ['foo', 'bar', 'baz']); //=> ['foo']
R.dropLast(3, ['foo', 'bar', 'baz']); //=> []
R.dropLast(4, ['foo', 'bar', 'baz']); //=> []
R.dropLast(3, 'ramda');               //=> 'ra'

equals

• Returns true if its arguments are equivalent, false otherwise. Handles cyclical data structures. Dispatches symmetrically to the equals methods of both arguments, if present.

R.equals(1, 1); //=> true
R.equals(1, '1'); //=> false
R.equals([1, 2, 3], [1, 2, 3]); //=> true

var a = {}; a.v = a;
var b = {}; b.v = b;
R.equals(a, b); //=> true

filter

• Takes a predicate and a "filterable", and returns a new filterable of the same type containing the members of the given filterable which satisfy the given predicate. Dispatches to the filter method of the second argument, if present. Acts as a transducer if a transformer is given in list position.

var isEven = n => n % 2 === 0;

R.filter(isEven, [1, 2, 3, 4]); //=> [2, 4]

R.filter(isEven, {a: 1, b: 2, c: 3, d: 4}); //=> {b: 2, d: 4}

find

• Returns the first element of the list which matches the predicate, or undefined if no element matches. Dispatches to the find method of the second argument, if present. Acts as a transducer if a transformer is given in list position.

var xs = [{a: 1}, {a: 2}, {a: 3}];
R.find(R.propEq('a', 2))(xs); //=> {a: 2}
R.find(R.propEq('a', 4))(xs); //=> undefined

findIndex

• Returns the index of the first element of the list which matches the predicate, or -1 if no element matches. Dispatches to the findIndex method of the second argument, if present. Acts as a transducer if a transformer is given in list position.

var xs = [{a: 1}, {a: 2}, {a: 3}];
R.findIndex(R.propEq('a', 2))(xs); //=> 1
R.findIndex(R.propEq('a', 4))(xs); //=> -1

flatten

• Returns a new list by pulling every item out of it (and all its sub-arrays) and putting them in a new array, depth-first.

R.flatten([1, 2, [3, 4], 5, [6, [7, 8, [9, [10, 11], 12]]]]);
//=> [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12]

head

• Returns the first element of the given list or string. In some libraries this function is named first.

R.head(['fi', 'fo', 'fum']); //=> 'fi'
R.head([]); //=> undefined

R.head('abc'); //=> 'a'
R.head(''); //=> ''

indexOf

• Returns the position of the first occurrence of an item in an array, or -1 if the item is not included in the array. R.equals is used to determine equality.

R.indexOf(3, [1,2,3,4]); //=> 2
R.indexOf(10, [1,2,3,4]); //=> -1

init

• Returns all but the last element of the given list or string.

R.init([1, 2, 3]);  //=> [1, 2]
R.init([1, 2]);     //=> [1]
R.init([1]);        //=> []
R.init([]);         //=> []

R.init('abc');  //=> 'ab'
R.init('ab');   //=> 'a'
R.init('a');    //=> ''
R.init('');     //=> ''

join

• Returns a string made by inserting the separator between each element and concatenating all the elements into a single string.

var spacer = R.join(' ');
spacer(['a', 2, 3.4]);   //=> 'a 2 3.4'
R.join('|', [1, 2, 3]);    //=> '1|2|3'

last

• Returns the last element of the given list or string.

R.last(['fi', 'fo', 'fum']); //=> 'fum'
R.last([]); //=> undefined

R.last('abc'); //=> 'c'
R.last(''); //=> ''

length

• Returns the number of elements in the array by returning list.length.

R.length([]); //=> 0
R.length([1, 2, 3]); //=> 3

map

• Takes a function and a functor, applies the function to each of the functor's values, and returns a functor of the same shape. Ramda provides suitable map implementations for Array and Object, so this function may be applied to [1, 2, 3] or {x: 1, y: 2, z: 3}. Dispatches to the map method of the second argument, if present. Acts as a transducer if a transformer is given in list position. Also treats functions as functors and will compose them together.

var double = x => x * 2;

R.map(double, [1, 2, 3]); //=> [2, 4, 6]

R.map(double, {x: 1, y: 2, z: 3}); //=> {x: 2, y: 4, z: 6}

match

• Tests a regular expression against a String. Note that this function will return an empty array when there are no matches. This differs from String.prototype.match which returns null when there are no matches.

R.match(/([a-z]a)/g, 'bananas'); //=> ['ba', 'na', 'na']
R.match(/a/, 'b'); //=> []
R.match(/a/, null); //=> TypeError: null does not have a method named "match"

merge

• Create 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, the value from the second object will be used.

R.merge({ 'name': 'fred', 'age': 10 }, { 'age': 40 });
//=> { 'name': 'fred', 'age': 40 }

var resetToDefault = R.merge(R.__, {x: 0});
resetToDefault({x: 5, y: 2}); //=> {x: 0, y: 2}

omit

• Returns a partial copy of an object omitting the keys specified.

R.omit(['a', 'd'], {a: 1, b: 2, c: 3, d: 4}); //=> {b: 2, c: 3}

path

• Retrieve the value at a given path.

R.path(['a', 'b'], {a: {b: 2}}); //=> 2
R.path(['a', 'b'], {c: {b: 2}}); //=> undefined

pick

• Returns a partial copy of an object containing only the keys specified. If the key does not exist, the property is ignored.

R.pick(['a', 'd'], {a: 1, b: 2, c: 3, d: 4}); //=> {a: 1, d: 4}
R.pick(['a', 'e', 'f'], {a: 1, b: 2, c: 3, d: 4}); //=> {a: 1}

prepend

• Returns a new list with the given element at the front, followed by the contents of the list.

R.prepend('fee', ['fi', 'fo', 'fum']); //=> ['fee', 'fi', 'fo', 'fum']

prop

• Returns a function that when supplied an object returns the indicated property of that object, if it exists.

R.prop('x', {x: 100}); //=> 100
R.prop('x', {}); //=> undefined

propEq

• Returns true if the specified object property is equal, in R.equals terms, to the given value; false otherwise.

var abby = {name: 'Abby', age: 7, hair: 'blond'};
var fred = {name: 'Fred', age: 12, hair: 'brown'};
var rusty = {name: 'Rusty', age: 10, hair: 'brown'};
var alois = {name: 'Alois', age: 15, disposition: 'surly'};
var kids = [abby, fred, rusty, alois];
var hasBrownHair = R.propEq('hair', 'brown');
R.filter(hasBrownHair, kids); //=> [fred, rusty]

range

• Returns a list of numbers from from (inclusive) to to (exclusive).

R.range(1, 5);    //=> [1, 2, 3, 4]
R.range(50, 53);  //=> [50, 51, 52]

repeat

• Returns a fixed list of size n containing a specified identical value.

R.repeat('hi', 5); //=> ['hi', 'hi', 'hi', 'hi', 'hi']

var obj = {};
var repeatedObjs = R.repeat(obj, 5); //=> [{}, {}, {}, {}, {}]
repeatedObjs[0] === repeatedObjs[1]; //=> true

replace

• Replace a substring or regex match in a string with a replacement.

R.replace('foo', 'bar', 'foo foo foo'); //=> 'bar foo foo'
R.replace(/foo/, 'bar', 'foo foo foo'); //=> 'bar foo foo'

// Use the "g" (global) flag to replace all occurrences:
R.replace(/foo/g, 'bar', 'foo foo foo'); //=> 'bar bar bar'

sort

• Returns a copy of the list, sorted according to the comparator function, which should accept two values at a time and return a negative number if the first value is smaller, a positive number if it's larger, and zero if they are equal. Please note that this is a copy of the list. It does not modify the original.

var diff = function(a, b) { return a - b; };
R.sort(diff, [4,2,7,5]); //=> [2, 4, 5, 7]

sortBy

• Sorts the list according to the supplied function.

var sortByFirstItem = R.sortBy(R.prop(0));
var sortByNameCaseInsensitive = R.sortBy(R.compose(R.toLower, R.prop('name')));
var pairs = [[-1, 1], [-2, 2], [-3, 3]];
sortByFirstItem(pairs); //=> [[-3, 3], [-2, 2], [-1, 1]]
var alice = {
  name: 'ALICE',
  age: 101
};
var bob = {
  name: 'Bob',
  age: -10
};
var clara = {
  name: 'clara',
  age: 314.159
};
var people = [clara, bob, alice];
sortByNameCaseInsensitive(people); //=> [alice, bob, clara]

split

• Splits a string into an array of strings based on the given separator.

var pathComponents = R.split('/');
R.tail(pathComponents('/usr/local/bin/node')); //=> ['usr', 'local', 'bin', 'node']

R.split('.', 'a.b.c.xyz.d'); //=> ['a', 'b', 'c', 'xyz', 'd']

splitEvery

• Splits a collection into slices of the specified length.

R.splitEvery(3, [1, 2, 3, 4, 5, 6, 7]); //=> [[1, 2, 3], [4, 5, 6], [7]]
R.splitEvery(3, 'foobarbaz'); //=> ['foo', 'bar', 'baz']

subtract

• Subtracts its second argument from its first argument.

R.subtract(10, 8); //=> 2

var minus5 = R.subtract(R.__, 5);
minus5(17); //=> 12

var complementaryAngle = R.subtract(90);
complementaryAngle(30); //=> 60
complementaryAngle(72); //=> 18

tail

• Returns all but the first element of the given list or string (or object with a tail method). Dispatches to the slice method of the first argument, if present.

R.tail([1, 2, 3]);  //=> [2, 3]
R.tail([1, 2]);     //=> [2]
R.tail([1]);        //=> []
R.tail([]);         //=> []

R.tail('abc');  //=> 'bc'
R.tail('ab');   //=> 'b'
R.tail('a');    //=> ''
R.tail('');     //=> ''

take

• Returns the first n elements of the given list, string, or transducer/transformer (or object with a take method). Dispatches to the take method of the second argument, if present.

R.take(1, ['foo', 'bar', 'baz']); //=> ['foo']
R.take(2, ['foo', 'bar', 'baz']); //=> ['foo', 'bar']
R.take(3, ['foo', 'bar', 'baz']); //=> ['foo', 'bar', 'baz']
R.take(4, ['foo', 'bar', 'baz']); //=> ['foo', 'bar', 'baz']
R.take(3, 'ramda');               //=> 'ram'

var personnel = [
  'Dave Brubeck',
  'Paul Desmond',
  'Eugene Wright',
  'Joe Morello',
  'Gerry Mulligan',
  'Bob Bates',
  'Joe Dodge',
  'Ron Crotty'
];

var takeFive = R.take(5);
takeFive(personnel);
//=> ['Dave Brubeck', 'Paul Desmond', 'Eugene Wright', 'Joe Morello', 'Gerry Mulligan']

takeLast

• Returns a new list containing the last n elements of the given list. If n > list.length, returns a list of list.length elements.

R.takeLast(1, ['foo', 'bar', 'baz']); //=> ['baz']
R.takeLast(2, ['foo', 'bar', 'baz']); //=> ['bar', 'baz']
R.takeLast(3, ['foo', 'bar', 'baz']); //=> ['foo', 'bar', 'baz']
R.takeLast(4, ['foo', 'bar', 'baz']); //=> ['foo', 'bar', 'baz']
R.takeLast(3, 'ramda');               //=> 'mda'

test

• Determines whether a given string matches a given regular expression.

R.test(/^x/, 'xyz'); //=> true
R.test(/^y/, 'xyz'); //=> false

toLower

• The lower case version of a string.

R.toLower('XYZ'); //=> 'xyz'

toUpper

• The upper case version of a string.

R.toUpper('abc'); //=> 'ABC'

trim

• Removes (strips) whitespace from both ends of the string.

R.trim('   xyz  '); //=> 'xyz'
R.map(R.trim, R.split(',', 'x, y, z')); //=> ['x', 'y', 'z']

type

• Gives a single-word string description of the (native) type of a value, returning such answers as 'Object', 'Number', 'Array', or 'Null'. Does not attempt to distinguish user Object types any further, reporting them all as 'Object'.

R.type({}); //=> "Object"
R.type(1); //=> "Number"
R.type(false); //=> "Boolean"
R.type('s'); //=> "String"
R.type(null); //=> "Null"
R.type([]); //=> "Array"
R.type(/[A-z]/); //=> "RegExp"

uniq

• Returns a new list containing only one copy of each element in the original list. R.equals is used to determine equality.

R.uniq([1, 1, 2, 1]); //=> [1, 2]
R.uniq([1, '1']);     //=> [1, '1']
R.uniq([[42], [42]]); //=> [[42]]

update

• Returns a new copy of the array with the element at the provided index replaced with the given value.

R.update(1, 11, [0, 1, 2]);     //=> [0, 11, 2]
R.update(1)(11)([0, 1, 2]);     //=> [0, 11, 2]

values

• Returns a list of all the enumerable own properties of the supplied object. Note that the order of the output array is not guaranteed across different JS platforms.

R.values({a: 1, b: 2, c: 3}); //=> [1, 2, 3]