Yakulu / rambda

Faster and smaller alternative to Ramda

Rambda

Faster alternative to Ramda - Documentation

• Example use
• Install
• Differences between Rambda and Ramda
• API
• Benchmark
• Use with ES5
• Changelog
• Additional info
• Browse by category

Rambda's advantages

• Tree-shaking

Currenly Rambda is more tree-shakable than Ramda as you can see in this tree-shaking example.

------------------  --------
file                size
------------------  --------
rollup/rambdax      206 B
rollup/ramdaBabel   276 B
rollup/lodash       278 B
rollup/rambda       785 B
parcel/lodash       1.2 KB
parcel/rambdax      1.2 KB
parcel/ramda        1.2 KB
parcel/rambda       1.2 KB
parcel/ramdaBabel   1.23 KB
webpack/rambda      2 KB
webpack/ramda       7.3 KB
webpack/ramdaBabel  8.36 KB
webpack/rambdax     26.71 KB
webpack/lodash      70.76 KB
rollup/ramda        92.16 KB

Also latest results of bundle-phobia-cli:

ℹ ramda (0.26.1) has 0 dependencies for a weight of 51.92KB (12.27KB gzipped)
ℹ rambda (2.1.1) has 0 dependencies for a weight of 13.28KB (3.32KB gzipped)
ℹ rambdax (1.3.0) has 0 dependencies for a weight of 35.7KB (10.16KB gzipped)

• Speed

Rambda is generally more performant than Ramda as the benchmarks can prove that.

You can clone this repo and run yarn run benchmark all to see for yourself.

• dot notation for R.path

Standard 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} })

• comma notation for R.pick and R.omit

Similar 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

• Typescript included

Typescript definitions are included in the library, in comparison to Ramda, where you need to additionally install @types/ramda.

---

Rambda partially shadows Ramda's API, which means that you need to check Rambda's documentation to assure that all the methods you need are available.

Example use

import {compose, map, filter} from 'rambda'

const result = compose(
  map(x => x * 2),
  filter(x => x > 2)
)([1, 2, 3, 4])
// => [6, 8]

You can test this example in Rambda's REPL

Install

• Use yarn add rambda for Webpack and Node.js usage

• For UMD usage either use ./dist/rambda.umd.js or following CDN link:

https://unpkg.com/rambda@2.0.0/dist/rambda.umd.js

Differences between Rambda and Ramda

• Rambda's type detect async functions and unresolved Promises. The returned values are 'Async' and 'Promise'.

• Rambda's type handle Not a number values and it returns NaN in this case.

• Rambda's path accepts dot notation('x.y' same as ['x','y'])

• Rambda's pick and omit accept comma notation('x,y' same as ['x','y'])

• Rambda's map and filter pass object key as second argument when mapping over objects.

• Rambda's map and filter pass array index as second argument when mapping over arrays.

• Rambda's all, allPass, any, anyPass, findIndex and reject are passing index as second argument to the predicate function.

• Rambda's defaultTo accept indefinite number of arguments when non curried, i.e. R.defaultTo(2, foo, bar, baz).

• Rambda's startsWith/endsWith work only with strings, instead with array and strings.

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

• Rambda's flip works only for functions expecting two arguments.

• Rambda's partial doesn't need the input arguments to be wrapped as array.

• Rambda's partialCurry is not part of Ramda API.

• Rambda's includes acts as curried Javascript includes, while Ramda version uses R.equals to check if a list contains certain value. Also Ramda version will throw an error if input is neither string nor array, while Rambda version will return false.

If you need more Ramda methods in Rambda, you may either submit a PR or check the extended version of Rambda - Rambdax. In case of the former, you may want to consult with Rambda contribution guidelines.

API

---

add

add(a: number, b: number): number

R.add(2, 3) // =>  5

Source

Try in REPL

---

adjust

adjust(replaceFn: Function, i: number, arr: T[]): T[]

It replaces i index in arr with the result of replaceFn(arr[i]).

R.adjust(
  a => a + 1,
  0,
  [0, 100]
) // => [1, 100]

Source

Try in REPL

---

all

all(fn: Function, arr: T[]): boolean

It returns true, if all members of array arr returns true, when applied as argument to function fn.

const arr = [ 0, 1, 2, 3, 4 ]
const fn = x => x > -1

const result = R.all(fn, arr)
// => true

Source

Try in REPL

---

allPass

allPass(rules: Function[], input: any): boolean

It returns true, if all functions of rules return true, when input is their argument.

const input = {
  a : 1,
  b : 2,
}
const rules = [
  x => x.a === 1,
  x => x.b === 2,
]
const result = R.allPass(rules, input) // => true

Source

Try in REPL

---

always

always(x: any): Function

It returns function that always returns x.

const fn = R.always(7)

console.log(fn())// => 7

Source

Try in REPL

---

any

any(condition: Function, arr: T[]): boolean

It returns true, if at least one member of arr returns true, when passed to the condition function.

R.any(a => a * a > 8)([1, 2, 3])
// => true

Source

Try in REPL

---

anyPass

anyPass(conditions: Function[]): Function

const isBig = a => a > 20
const isOdd = a => a % 2 === 1

const result = R.anyPass(
  [isBig, isOdd]
)(11)
// => true

Source

Try in REPL

---

append

append(valueToAppend: T, arr: T[]): T[]

R.append(
  'foo',
  ['bar', 'baz']
) // => ['bar', 'baz', 'foo']

Source

Try in REPL

---

assoc

assoc(prop: any, value: any, obj: object): object

Makes a shallow clone of obj, setting or overriding the property prop with the value value. Note that 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}

Source

Try in REPL

---

both

both(firstCondition: Function, secondCondition: Function, input: any): boolean

It returns true, if both function firstCondition and function secondCondition return true, when input is their argument.

const fn = R.both(
  a => a > 10,
  a => a < 20
)
console.log(fn(15)) //=> true
console.log(fn(30)) //=> false

Source

Try in REPL

---

clone

clone(objOrArr: T|T[]): T|T[] both Creates a deep copy of the value which may contain (nested) Arrays and Objects, Numbers, Strings, Booleans and Dates. Functions are assigned by reference rather than copied

const objects = [{}, {}, {}];
const objectsClone = R.clone(objects);
objects === objectsClone; //=> false
objects[0] === objectsClone[0]; //=> false

Source

Try in REPL

---

compose

compose(fn1: Function, ... , fnN: Function): any

It performs right-to-left function composition.

const result = R.compose(
  R.map(x => x * 2),both
  R.filter(x => x > 2)
)([1, 2, 3, 4])

// => [6, 8]

Source

Try in REPL

---

complement

complement(fn: Function): Function

It returns complemented function that accept input as argument.

The return value of complemented is the negative boolean value of fn(input).

const fn = R.complement(x => !x)

const result = fn(false) // => false

Source

Try in REPL

---

concat

concat(x: T[]|string, y: T[]|string): T[]|string

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'

Source

Try in REPL

---

contains

contains(valueToFind: T, arr: T[]): boolean

It returns true, if valueToFind is part of arr.

Note that while new versions of Ramda depricate this method, contains will remain in this library.

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

Source

Try in REPL

---

curry

curry(fn: Function): Function

It 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)
const result = g(4) // => 10

Source

Try in REPL

---

dec

dec(x: number): number

It decrements a number.

R.dec(2) // => 1

Source

Try in REPL

---

defaultTo

defaultTo(defaultValue: T, ...inputArguments: any[]): T

It either returns defaultValue, if all of inputArguments are undefined, null or NaN.

Or it returns the first truthy inputArguments instance(from left to right).

R.defaultTo('foo', undefined) // => 'foo'
R.defaultTo('foo', undefined, null, NaN) // => 'foo'
R.defaultTo('foo', undefined, 'bar', NaN, 'baz') // => 'bar'
R.defaultTo('foo', undefined, null, NaN, 'baz') // => 'baz'
R.defaultTo('foo', 'bar') // => 'bar'

Source

Try in REPL

---

dissoc

dissoc(prop: any, obj: object): object

It returns a new object that does not contain a prop property.

R.dissoc('b', {a: 1, b: 2, c: 3})
//=> {a: 1, c: 3}

Source

Try in REPL

---

divide

R.divide(71, 100) // => 0.71

---

drop

drop(howManyToDrop: number, arrOrStr: T[]|string): T[]|String

It returns arrOrStr with howManyToDrop items dropped from the left.

R.drop(1, ['foo', 'bar', 'baz']) // => ['bar', 'baz']
R.drop(1, 'foo')  // => 'oo'

Source

Try in REPL

---

dropLast

dropLast(howManyToDrop: number, arrOrStr: T[]|String): T[]|String

It returns arrOrStr with howManyToDrop items dropped from the right.

R.dropLast(1, ['foo', 'bar', 'baz']) // => ['foo', 'bar']
R.dropLast(1, 'foo')  // => 'fo'

Source

Try in REPL

---

endsWith

endsWith(x: string, str: string): boolean

R.endsWith(
  'bar',
  'foo-bar'
) // => true

R.endsWith(
  'foo',
  'foo-bar'
) // => false

Source

Try in REPL

---

either

either(firstCondition: Function, secondCondition: Function): Function

R.either(
  a => a > 10,
  a => a % 2 === 0
)(15) //=> true

Source

Try in REPL

---

equals

equals(a: any, b: any): boolean

It returns equality match between a and b.

It doesn't handle cyclical data structures.

R.equals(
  [1, {a:2}, [{b:3}]],
  [1, {a:2}, [{b:3}]]
) // => true

Source

Try in REPL

---

F

R.F() // => false

Source

---

filter

filter(filterFn: Function, x: Array|Object): Array|Object

It filters x iterable over boolean returning filterFn.

const filterFn = a => a % 2 === 0

const result = R.filter(filterFn, [1, 2, 3, 4])
// => [2, 4]

The method works with objects as well.

Note that unlike Ramda's filter, here object keys are passed as second argument to filterFn.

const result = R.filter((val, prop)=>{
  return prop === 'a' || val === 2
}, {a: 1, b: 2, c: 3})

// => {a: 1, b: 2}

Source

Try in REPL

---

find

find(findFn: Function, arr: T[]): T|undefined

It returns undefined or the first element of arr satisfying findFn.

const findFn = a => R.type(a.foo) === 'Number'
const arr = [{foo: 'bar'}, {foo: 1}]

const result = R.find(findFn, arr)
// => {foo: 1}

Source

Try in REPL

---

findIndex

findIndex(findFn: Function, arr: T[]): number

It 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}]

const result = R.findIndex(findFn, arr)
// => 1

Source

Try in REPL

---

flatten

flatten(arr: any[]): any[]

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

Source

Try in REPL

---

flip

flip(fn: Function): Function

It returns function which calls fn with exchanged first and second argument.

const subtractFlip = R.flip(R.subtract)

const result = subtractFlip(1,7)
// => 6

Source

Try in REPL

---

forEach

forEach(fn: Function, arr: Array): Array

It applies function fn over all members of array arr and returns arr.

const sideEffect = {}
const result = R.forEach(
  x => sideEffect[`foo${x}`] = x
)([1, 2])

console.log(sideEffect) //=> {foo1 : 1, foo2 : 2}
console.log(result) //=> [1, 2]

Note, that unlike Ramda's forEach, Rambda's one doesn't dispatch to forEach method of arr if arr has such method.

Source

Try in REPL

---

fromPairs

fromPairs(list: any[]): object

It transforms a list to an object.

const list = [ [ 'a', 1 ], [ 'b', 2 ], [ 'c', [ 3, 4 ] ] ]
const expected = {
  a : 1,
  b : 2,
  c : [ 3, 4 ],
}

const result = R.fromPairs(list)
// expected === result

Source

Try in REPL

---

groupBy

groupBy(fn: Function, arr: Array): Object

It groups array arr by provided selector function fn.

R.groupBy(
  x => x.length,
  [ 'a', 'b', 'aa', 'bb' ]
)
// => { '1': ['a', 'b'], '2': ['aa', 'bb'] }

Source

Try in REPL

---

has

has(prop: string, obj: Object): boolean

• It returns true if obj has property prop.

R.has('a', {a: 1}) // => true
R.has('b', {a: 1}) // => false

Source

Try in REPL

---

head

head(arrOrStr: T[]|string): T|string

It returns the first element of arrOrStr.

R.head([1, 2, 3]) // => 1
R.head('foo') // => 'f'

Source

Try in REPL

---

identity

identity(x: T): T

It just passes back the supplied arguments.

R.identity(7) // => 7

Source

Try in REPL

---

ifElse

ifElse(condition: Function|boolean, ifFn: Function, elseFn: Function): Function

It returns function, which expect input as argument and returns finalResult.

When this function is called, a value answer is generated as a result of condition(input).

If answer is true, then finalResult is equal to ifFn(input). If answer is false, then finalResult is equal to elseFn(input).

const fn = R.ifElse(
 x => x > 10,
 x => x*2,
 x => x*10
)

const result = fn(8)
// => 80

Source

Try in REPL

---

inc

inc(x: number): number

It increments a number.

R.inc(1) // => 2

Source

Try in REPL

---

includes

If input is neither string nor array, then this method will return false.

includes(target: any, input: any): boolean

R.includes(1, [1, 2]) // => true
R.includes('oo', 'foo') // => true
R.includes('z', 'foo') // => false
R.includes('z', null) // => false

!! Note that this method is not part of Ramda API.

Source

Try in REPL

---

indexBy

indexBy(fn: Function, arr: T[]): Object

It indexes array arr as an object with provided selector function fn.

R.indexBy(
  x => x.id,
  [ {id: 1}, {id: 2} ]
)
// => { 1: {id: 1}, 2: {id: 2} }

Source

Try in REPL

---

indexOf

indexOf(valueToFind: any, arr: T[]): number

It returns -1 or the index of the first element of arr equal of valueToFind.

R.indexOf(1, [1, 2]) // => 0
R.indexOf(0, [1, 2]) // => -1

Source

Try in REPL

---

init

init(arrOrStr: T[]|string): T[]|string

• It returns all but the last element of arrOrStr.

R.init([1, 2, 3])  // => [1, 2]
R.init('foo')  // => 'fo'

Source

Try in REPL

---

is

is(xPrototype: any, x: any): boolean

It returns true is x is instance of xPrototype.

R.is(String, 'foo')  // => true
R.is(Array, 1)  // => false

Source

Try in REPL

---

isNil

isNil(x: any): boolean

It returns true is x is either null or undefined.

R.isNil(null)  // => true
R.isNil(1)  // => false

Source

Try in REPL

---

isEmpty

isEmpty(x: any): boolean

It returns true is x is empty.

R.isEmpty(null)  // => true
R.isEmpty(undefined)  // => true
R.isEmpty('')  // => true
R.isEmpty([])  // => true
R.isEmpty({})  // => true

Source

Try in REPL

---

join

join(separator: string, arr: T[]): string

R.join('-', [1, 2, 3])  // => '1-2-3'

Source

Try in REPL

---

keys

keys(x: Object): string[]

R.keys({a:1, b:2})  // => ['a', 'b']

Source

Try in REPL

---

last

last(arrOrStr: T[]|string): T|string

• It returns the last element of arrOrStr.

R.last(['foo', 'bar', 'baz']) // => 'baz'
R.last('foo') // => 'o'

Source

Try in REPL

---

lastIndexOf

lastIndexOf(x: any, arr: T[]): number

It returns the last index of x in array arr.

R.equals is used to determine equality between x and members of arr.

Value -1 is returned if no x is found in arr.

R.lastIndexOf(1, [1, 2, 3, 1, 2]) // => 3
R.lastIndexOf(10, [1, 2, 3, 1, 2]) // => -1

Source

Try in REPL

---

length

length(arrOrStr: Array|String): Number

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

Source

Try in REPL

---

map

map(mapFn: Function, x: Array|Object): Array|Object

It returns the result of looping through iterable x with mapFn.

The method works with objects as well.

Note that unlike Ramda's map, here object keys are passed as second argument to mapFn.

const mapFn = x => x * 2
const resultWithArray = R.map(mapFn, [1, 2, 3])
// => [2, 4, 6]

const result = R.map((val, prop)=>{
  return `${prop}-${val}`
}, {a: 1, b: 2})
// => {a: 'a-1', b: 'b-2'}

Source

Try in REPL

---

match

match(regExpression: Regex, str: string): string[]

R.match(/([a-z]a)/g, 'bananas') // => ['ba', 'na', 'na']

Source

Try in REPL

---

max

max(x: Number|String, y: Number|String): Number|String

R.max(5,7) // => 7

Source

Try in REPL

---

maxBy

maxBy(fn: Function, x: Number|String, y: Number|String): Number|String

R.maxBy(Math.abs, 5, -7) // => -7

Source

Try in REPL

---

merge

merge(a: Object, b: Object)

It returns result of Object.assign({}, a, b).

R.merge({ 'foo': 0, 'bar': 1 }, { 'foo': 7 })
// => { 'foo': 7, 'bar': 1 }

Source

Try in REPL

---

min

min(x: Number|String, y: Number|String): Number|String

R.max(5,7) // => 5

Source

Try in REPL

---

minBy

minBy(fn: Function, x: Number|String, y: Number|String): Number|String

R.minBy(Math.abs, -5, -7) // => -5

Source

Try in REPL

---

modulo

modulo(a: number, b: number):numberNumber

It returns the remainder of operation a/b.

R.module(14, 3) // => 2

Source

Try in REPL

---

multiply

multiply(a: number, b: number): number

It returns the result of operation a*b.

R.multiply(4, 3) // => 12

Source

Try in REPL

---

not

not(x: any): boolean

It returns inverted boolean version of input x.

R.not(true) //=> false
R.not(false) //=> true
R.not(0) //=> true
R.not(1) //=> false

Source

Try in REPL

---

omit

omit(propsToOmit: string[]|string, obj: Object): Object

It returns a partial copy of an obj with omitting propsToOmit

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

Source

Try in REPL

---

path

path(pathToSearch: string[]|string, obj: Object): any

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.

R.path('a.b', {a: {b: 1}}) // => 1

Source

Try in REPL

---

pathOr

pathOr(defaultValue: any, pathToSearch: string[]|string, obj: Object): any

pathFound is the result of calling R.path(pathToSearch, obj).

If pathFound is undefined, null or NaN, then defaultValue will be returned.

pathFound is returned in any other case.

R.pathOr(1, 'a.b', {a: {b: 2}}) // => 2
R.pathOr(1, ['a', 'b'], {a: {b: 2}}) // => 2
R.pathOr(1, ['a', 'c'], {a: {b: 2}}) // => 1

Source

Try in REPL

---

partial

partial(fn: Function, ...inputs: any[]): Function | any

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.

const fn = (salutation, title, firstName, lastName) => salutation + ', ' + title + ' ' + firstName + ' ' + lastName + '!'

const canPassAnyNumberOfArguments = partial(fn, 'Hello', 'Ms.')
const finalFn = canPassAnyNumberOfArguments('foo')

finalFn('bar') // =>  'Hello, Ms. foo bar!'

---

partialCurry

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})
const result = 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

Source

Try in REPL

---

pick

pick(propsToPick: string[], obj: Object): Object

It returns a partial copy of an obj containing only propsToPick properties.

R.pick(['a', 'c'], {a: 1, b: 2}) // => {a: 1}

Source

Try in REPL

---

pipe

pipe(fn1: Function, ... , fnN: Function): any

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]

Source

Try in REPL

---

pluck

pluck(property: string, arr: Object[]): any[]

It returns list of the values of property taken from the objects in array of objects arr.

R.pluck('a')([{a: 1}, {a: 2}, {b: 3}]) // => [1, 2]

Source

Try in REPL

---

prepend

prepend(x: T, arr: T[]): T[]

It adds x to the start of the array arr.

R.prepend('foo', ['bar', 'baz']) // => ['foo', 'bar', 'baz']

Source

Try in REPL

---

prop

prop(propToFind: string, obj: Object): any

It returns undefined or the value of property propToFind in obj

R.prop('x', {x: 100}) // => 100
R.prop('x', {a: 1}) // => undefined

Source

Try in REPL

---

propEq

propEq(propToFind: string, valueToMatch: any, obj: Object): boolean

It returns true if obj has property propToFind and its value is equal to valueToMatch.

const propToFind = 'foo'
const valueToMatch = 0

const result = R.propEq(propToFind, valueToMatch)({foo: 0})
// => true

Source

Try in REPL

---

range

range(start: number, end: number): number[]

It returns a array of numbers from start(inclusive) to end(exclusive).

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

Source

Try in REPL

---

reduce

reduce(iteratorFn: Function, accumulator: any, array: T[]): any

const iteratorFn = (acc, val) => acc + val
const result = R.reduce(iteratorFn, 1, [1, 2, 3])
// => 7

Source

Try in REPL

---

reject

reject(fn: Function, arr: T[]): T[]

It has the opposite effect of R.filter.

It will return those members of arr that return false when applied to function fn.

const fn = x => x % 2 === 1

const result = R.reject(fn, [1, 2, 3, 4])
// => [2, 4]

Source

Try in REPL

---

repeat

repeat(valueToRepeat: T, num: number): T[]

R.repeat('foo', 2) // => ['foo', 'foo']

Source

Try in REPL

---

replace

replace(strOrRegex: string|Regex, replacer: string, str: string): string

It replaces 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'

Source

Try in REPL

---

reverse

reverse(str: T[]): T[]

const arr = [1, 2]

const result = R.reverse(arr)
// => [2, 1]

Source

Try in REPL

---

sort

sort(sortFn: Function, arr: T[]): T[]

It returns copy of arr sorted by sortFn.

Note that sortFn must return a number type.

const sortFn = (a, b) => a - b

const result = R.sort(sortFn, [3, 1, 2])
// => [1, 2, 3]

Source

Try in REPL

---

sortBy

sortBy(sortFn: Function, arr: T[]): T[]

It returns copy of arr sorted by sortFn.

Note that sortFn must return value for comparison.

const sortFn = obj => obj.foo

const result = R.sortBy(sortFn, [
  {foo: 1},
  {foo: 0}
])

const expectedResult = [ {foo: 0}, {foo: 1} ]
console.log(R.equals(result, expectedResult))
// => true

Source

Try in REPL

---

split

split(separator: string, str: string): string[]

R.split('-', 'a-b-c') // => ['a', 'b', 'c']

Source

Try in REPL

---

splitEvery

splitEvery(sliceLength: number, arrOrString: T[]|string): T[T[]]|string[]

• It splits arrOrStr into slices of sliceLength.

R.splitEvery(2, [1, 2, 3]) // => [[1, 2], [3]]
R.splitEvery(3, 'foobar') // => ['foo', 'bar']

Source

Try in REPL

---

startsWith

startsWith(x: string, str: string): boolean

R.startsWith(
  'foo',
  'foo-bar'
) // => true

R.startsWith(
  'bar',
  'foo-bar'
) // => false

Source

Try in REPL

---

subtract

subtract(a: number, b: number): number

R.subtract(3, 1) // => 2

Source

Try in REPL

---

T

R.T() // => true

Source

---

tail

tail(arrOrStr: T[]|string): T[]|string

• It returns all but the first element of arrOrStr

R.tail([1, 2, 3])  // => [2, 3]
R.tail('foo')  // => 'oo'

Source

Try in REPL

---

take

take(num: number, arrOrStr: T[]|string): T[]|string

• It returns the first num elements of arrOrStr.

R.take(1, ['foo', 'bar']) // => ['foo']
R.take(2, 'foo') // => 'fo'

Source

Try in REPL

---

takeLast

takeLast(num: number, arrOrStr: T[]|string): T[]|string

• It returns the last num elements of arrOrStr.

R.takeLast(1, ['foo', 'bar']) // => ['bar']
R.takeLast(2, 'foo') // => 'oo'

Source

Try in REPL

---

tap

tap(fn: Function, input: T): T

• It applies function to input and pass the input back. Use case is debuging in the middle of R.compose.

let a = 1
const sayX = x => (a = x)

const result = R.tap(sayX, 100)
// both `a` and `result` are `100`

Source

Try in REPL

---

test

test(regExpression: Regex, str: string): boolean

• Determines whether str matches regExpression

R.test(/^f/, 'foo')
// => true

Source

Try in REPL

---

times

times(fn: Function, n: number): T[]

It returns the result of applying function fn over members of range array. The range array includes numbers between 0 and n(exclusive).

R.times(R.identity, 5)
//=> [0, 1, 2, 3, 4]

Source

Try in REPL

---

toLower

toLower(str: string): string

R.toLower('FOO') // => 'foo'

Source

Try in REPL

---

toPairs

toPairs(obj: object): any[]

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)
// expected === result

Source

Try in REPL

---

toString

toString(x: any): string

R.toString([1, 2]) // => '1,2'

Source

Try in REPL

---

toUpper

toUpper(str: string): string

R.toUpper('foo') // => 'FOO'

Source

Try in REPL

---

trim

trim(str: string): string

R.trim('  foo  ') // => 'foo'

Source

Try in REPL

---

type

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'

Source

Try in REPL

---

uniq

uniq(arr: T[]): T[]

It returns a new array containing only one copy of each element in arr.

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

Source

Try in REPL

---

uniqWith

uniqWith(fn: Function, arr: T[]): T[]

It returns a new array containing only one copy of each element in arr according to boolean returning function fn.

const arr = [
  {id: 0, title:'foo'},
  {id: 1, title:'bar'},
  {id: 2, title:'baz'},
  {id: 3, title:'foo'},
  {id: 4, title:'bar'},
]

const expectedResult = [
  {id: 0, title:'foo'},
  {id: 1, title:'bar'},
  {id: 2, title:'baz'},
]

const fn = (x,y) => x.title === y.title

const result = R.uniqWith(fn, arr)

console.log(R.equals(result, expectedResult)) // => true

Source

Try in REPL

---

update

update(i: number, replaceValue: T, arr: T[]): T[]

It returns a new copy of the arr with the element at i index replaced with replaceValue.

R.update(0, 'foo', ['bar', 'baz'])
// => ['foo', baz]

Source

Try in REPL

---

values

values(obj: Object): Array

It returns array with of all values in obj.

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

Source

Try in REPL

---

without

without(a: T[], b: T[]): T[]

It will return a new array based on b array.

This array contains all members of b array, that doesn't exist in a array.

Method R.equals is used to determine the existance of b members in a array.

R.without([1, 2], [1, 2, 3, 4])
// => [3, 4]

Source

Try in REPL

---

zip

zip(a: K[], b: V[]): Array

It will return a new array containing tuples of equally positions items from both lists. The returned list will be truncated to match the length of the shortest supplied list.

R.zip([1, 2], ['A', 'B'])
// => [[1, 'A'], [2, 'B']]

// truncates to shortest list
R.zip([1, 2, 3, 4], ['A', 'B'])
// => [[1, 'A'], [2, 'B']]

Source

Try in REPL

---

zipObj

zipObj(a: K[], b: V[]): Object

It will return a new object with keys of a array and values of b array.

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

// truncates to shortest list
R.zipObj(['a', 'b', 'c'], [1, 2])
//=> {a: 1, b: 2}

Source

Try in REPL

---

---

Benchmark

Results of running yarn benchmarks:

Running add.js
  3 tests completed.

  Rambda.add x 645,750,977 ops/sec ±1.21% (89 runs sampled)
  Ramda.add  x  61,329,732 ops/sec ±4.57% (75 runs sampled)
  Lodash.add x  49,915,718 ops/sec ±5.72% (74 runs sampled)

Running adjust.js
  2 tests completed.

  Rambda.adjust x 2,356,436 ops/sec ±4.24% (72 runs sampled)
  Ramda.adjust  x 8,249,572 ops/sec ±3.41% (76 runs sampled)

Running any.js
  3 tests completed.

  Rambda.any  x 14,673,511 ops/sec ±4.50% (74 runs sampled)
  Ramda.any   x  3,227,456 ops/sec ±5.51% (74 runs sampled)
  Lodash.some x 11,964,478 ops/sec ±3.52% (74 runs sampled)

Running append.js
  2 tests completed.

  Rambda.append x 3,020,920 ops/sec ±6.56% (70 runs sampled)
  Ramda         x 2,381,626 ops/sec ±8.22% (74 runs sampled)

Running assoc.js
  3 tests completed.

  Rambda.assoc x 1,091,819 ops/sec ±3.44% (82 runs sampled)
  Ramda.assoc  x 5,780,540 ops/sec ±7.26% (75 runs sampled)
  Lodash.set   x 7,025,930 ops/sec ±2.93% (84 runs sampled)

Running compose.js
  3 tests completed.

  Rambda.compose   x 9,908,504 ops/sec ±7.20% (80 runs sampled)
  Ramda            x   490,614 ops/sec ±3.65% (93 runs sampled)
  Lodash.flowRight x 1,947,909 ops/sec ±3.05% (83 runs sampled)

Running contains.js
  3 tests completed.

  Rambda.contains x  9,829,102 ops/sec ±5.41% (71 runs sampled)
  Ramda           x 20,822,670 ops/sec ±7.20% (81 runs sampled)
  Lodash.includes x 13,424,597 ops/sec ±1.43% (93 runs sampled)

Running drop.js
  2 tests completed.

  Rambda.drop x 13,421,844 ops/sec ±1.96% (94 runs sampled)
  Ramda       x  1,299,620 ops/sec ±0.56% (90 runs sampled)

Running dropLast.js
  2 tests completed.

  Rambda.dropLast x 12,256,336 ops/sec ±2.98% (83 runs sampled)
  Ramda           x    979,827 ops/sec ±0.85% (91 runs sampled)

Running endsWith.js
  2 tests completed.

  Rambda.endsWith:
  Ramda.endsWith  x 244,130 ops/sec ±0.80% (93 runs sampled)

Running equals.js
  3 tests completed.

  Rambda.equals  x 776,908 ops/sec ±0.36% (95 runs sampled)
  Ramda          x 130,283 ops/sec ±0.27% (96 runs sampled)
  Lodash.isEqual x 324,492 ops/sec ±1.54% (91 runs sampled)

Running filter.js
  3 tests completed.

  Rambda.filter x 8,972,564 ops/sec ±0.70% (93 runs sampled)
  Ramda         x 2,828,593 ops/sec ±1.28% (92 runs sampled)
  Lodash        x 7,988,026 ops/sec ±0.53% (91 runs sampled)

Running find.js
  3 tests completed.

  Rambda.find x 15,377,832 ops/sec ±1.19% (94 runs sampled)
  Ramda       x  3,552,442 ops/sec ±1.43% (93 runs sampled)
  Lodash      x  6,795,695 ops/sec ±2.68% (83 runs sampled)

Running findIndex.js
  3 tests completed.

  Rambda.findIndex x 74,769,765 ops/sec ±1.47% (89 runs sampled)
  Ramda            x  4,495,595 ops/sec ±0.29% (86 runs sampled)
  Lodash           x 18,412,494 ops/sec ±0.69% (94 runs sampled)

Running flatMap.js
  3 tests completed.

  Rambda.flatMap:
  Ramda.chain    x   693,304 ops/sec ±0.60% (92 runs sampled)
  Lodash.flatMap x 5,010,798 ops/sec ±2.65% (91 runs sampled)

Running flatten.js
  3 tests completed.

  Rambda.flatten x 11,422,824 ops/sec ±0.76% (83 runs sampled)
  Ramda          x    511,591 ops/sec ±1.15% (93 runs sampled)
  Lodash         x 11,886,203 ops/sec ±4.04% (90 runs sampled)

Running head.js
  3 tests completed.

  Rambda.head x 666,523,533 ops/sec ±2.28% (90 runs sampled)
  Ramda       x   4,108,249 ops/sec ±2.61% (81 runs sampled)
  Lodash      x 635,064,083 ops/sec ±2.33% (90 runs sampled)

Running headString.js
  2 tests completed.

  Rambda.head when string x 657,989,058 ops/sec ±2.97% (92 runs sampled)
  Ramda                   x   4,359,516 ops/sec ±2.60% (90 runs sampled)

Running indexOf.js
  3 tests completed.

  Rambda.indexOf x  70,001,108 ops/sec ±1.58% (88 runs sampled)
  Ramda          x  29,813,338 ops/sec ±1.77% (83 runs sampled)
  Lodash         x 113,836,928 ops/sec ±3.19% (84 runs sampled)

Running init.js
  3 tests completed.

  Rambda.init x 65,121,775 ops/sec ±0.55% (90 runs sampled)
  Ramda       x  3,826,157 ops/sec ±1.67% (90 runs sampled)
  Lodash      x 65,335,623 ops/sec ±0.53% (94 runs sampled)

Running initString.js
  2 tests completed.

  Rambda.init when string x 668,106,421 ops/sec ±0.28% (94 runs sampled)
  Ramda                   x   1,859,185 ops/sec ±0.39% (92 runs sampled)

Running last.js
  3 tests completed.

  Rambda.last x 685,930,416 ops/sec ±0.68% (92 runs sampled)
  Ramda       x   4,691,688 ops/sec ±0.40% (92 runs sampled)
  Lodash      x 661,001,582 ops/sec ±0.15% (92 runs sampled)

Running map.js
  3 tests completed.

  Rambda.map x 38,639,887 ops/sec ±2.84% (85 runs sampled)
  Ramda      x  3,183,185 ops/sec ±0.56% (90 runs sampled)
  Lodash     x 10,962,353 ops/sec ±0.67% (95 runs sampled)

Running match.js
  2 tests completed.

  Rambda.match x 5,426,665 ops/sec ±0.86% (91 runs sampled)
  Ramda        x 2,047,681 ops/sec ±1.77% (91 runs sampled)

Running merge.js
  3 tests completed.

  Rambda.merge x 1,863,285 ops/sec ±1.01% (94 runs sampled)
  Ramda        x 1,697,063 ops/sec ±0.57% (93 runs sampled)
  Lodash       x 3,204,496 ops/sec ±1.92% (93 runs sampled)

Running omit.js
  3 tests completed.

  Rambda.omit x 16,131,957 ops/sec ±2.29% (88 runs sampled)
  Ramda       x  5,550,336 ops/sec ±1.11% (87 runs sampled)
  Lodash      x    462,267 ops/sec ±0.48% (95 runs sampled)

Running path.js
  3 tests completed.

  Rambda.path x 19,324,789 ops/sec ±2.32% (84 runs sampled)
  Ramda       x 12,023,590 ops/sec ±0.56% (94 runs sampled)
  Lodash.get  x 23,917,540 ops/sec ±0.20% (91 runs sampled)

Running pick.js
  3 tests completed.

  Rambda#pick x 14,718,599 ops/sec ±1.11% (90 runs sampled)
  Ramda       x  2,743,200 ops/sec ±2.89% (88 runs sampled)
  Lodash      x  1,163,711 ops/sec ±0.65% (85 runs sampled)

Running pipe.js
  3 tests completed.

  Rambda.pipe x 4,882,396 ops/sec ±2.63% (84 runs sampled)
  Ramda       x   684,076 ops/sec ±0.36% (93 runs sampled)
  Lodash.flow x 2,249,643 ops/sec ±2.35% (87 runs sampled)

Running prop.js
  2 tests completed.

  Rambda#prop x 24,454,343 ops/sec ±2.82% (77 runs sampled)
  Ramda       x  2,465,343 ops/sec ±3.22% (86 runs sampled)

Running propEq.js
  2 tests completed.

  Rambda#propEq x 21,726,907 ops/sec ±2.71% (83 runs sampled)
  Ramda         x  2,529,510 ops/sec ±0.46% (92 runs sampled)

Running range.js
  3 tests completed.

  Rambda#range x 17,206,190 ops/sec ±0.96% (92 runs sampled)
  Ramda        x 10,920,367 ops/sec ±2.85% (86 runs sampled)
  Lodash       x 15,615,720 ops/sec ±2.36% (89 runs sampled)

Running reduce.js
  3 tests completed.

  Rambda#reduce x 9,780,084 ops/sec ±2.58% (88 runs sampled)
  Ramda         x 2,606,911 ops/sec ±1.13% (91 runs sampled)
  Lodash        x 8,901,216 ops/sec ±0.85% (9

Use with ES5

import omit from 'rambda/lib/omit'

Latest version that has this feature is 2.3.1

Changelog

• 2.10.2 Close issue #175 - missing typescript file

• 2.10.0 Approve huge and importamt PR #171 submitted by @helmuthdu - Add comments to each method, improve Typescript support

• 2.9.0 R.toPairs and R.fromPairs

• 2.8.0 Approve PR #165 R.clone

• 2.7.1 expose src | Discussed at issue #147

• 2.7.0 Approve PR #161 R.isEmpty

• 2.6.0 R.map, R.filter and R.forEach pass original object to iterator as third argument | Discussed at issue #147

• 2.5.0 Close issue #149 Add R.partial | R.type handles NaN

• 2.4.0 Major bump of Rollup; Stop building for ES5

• 2.3.1 Close issue #90 | Add string type of path in R.pathOr

• 2.3.0 Close issue #89 | Fix missing Number TS definition in R.type

• 2.2.0 R.defaultTo accepts indefinite number of input arguments. So the following is valid expression: const x = defaultTo('foo',null, null, 'bar')

• 2.1.0 Restore R.zip using WatermelonDB implementation.

• 2.0.0 Major version caused by removing of R.zip and R.addIndex. Issue #85 rightfully finds that the implementation of R.addIndex is not correct. This led to removing this method and also of R.zip as it had depended on it. The second change is that R.map, R.filter are passing array index as second argument when looping over arrays. The third change is that R.includes will return false if input is neigher string nor array. The previous behaviour was to throw an error. The last change is to increase the number of methods that are passing index as second argument to the predicate function.

• 1.2.6 Use src folder instead of modules

• 1.2.5 Fix omit typing

• 1.2.4 Add missing Typescript definitions - PR#82

• 1.2.3 Doesn't exist because NPM is great at handling errors.

• 1.2.2 Change curry method used across most of library methods

• 1.2.1 Add R.assoc | fix passing undefined to R.map and R.merge issue #77

• 1.2.0 Add R.min, R.minBy, R.max, R.maxBy, R.nth and R.keys

• 1.1.5 Close issue #74 R.zipObj

• 1.1.4 Close issue #71 CRA fail to build rambda

• 1.1.3 Approve PR #70 implement R.groupBy | Close issue #69

• 1.1.2 Approve PR #67 use babel-plugin-annotate-pure-calls

• 1.1.1 Approve PR #66 R.zip

• 1.1.0 R.compose accepts more than one input argument issue #65

• 1.0.13 Approve PR #64 R.indexOf

• 1.0.12 Close issue #61 make all functions modules

• 1.0.11 Close issue #60 problem with babelrc

• 1.0.10 Close issue #59 add R.dissoc

• 1.0.9 Close issue #58 - Incorrect R.equals

• 1.0.8 R.map and R.filter pass object properties when mapping over objects

• 1.0.7 Add R.uniqWith

• 1.0.6 Close issue #52 - ES5 compatible code

• 1.0.5 Close issue #51

• 1.0.4 Close issue #50 - add R.pipe typings

• 1.0.3 R.ifElse accept also boolean as condition argument

• 1.0.2 Remove typedDefaultTo and typedPathOr | Add R.pickAll and R.none

• 1.0.0 Major change as build is now ES6 not ES5 compatible (Related to issue #46)| Making Rambda fully tree-shakeable| Edit Typescript definition

• 0.9.8 Revert to ES5 compatible build - issue #46

• 0.9.7 Refactor for Rollup tree-shake | Remove R.padEnd and R.padStart

• 0.9.6 Close issue #44 - R.reverse mutates the array

• 0.9.5 Close issue #45 - invalid Typescript typings

• 0.9.4 Add R.reject and R.without (PR#41 PR#42) | Remove 'browser' field in package.json due to Webpack bug 4674

• 0.9.3 Add R.forEach and R.times

• 0.9.2 Add Typescript definitions

• 0.9.1 Close issue #36 - move current behaviour of defaultTo to a new method typedDefaultTo; make defaultTo follow Ramda spec; add pathOr; add typedPathOr.

• 0.9.0 Add R.pipe PR#35

• 0.8.9 Add R.isNil

• 0.8.8 Migrate to ES modules PR33 | Add R.flip to the API | R.map/filter works with objects

• 0.8.7 Change Webpack with Rollup - PR29

• 0.8.6 Add R.tap and R.identity

• 0.8.5 Add R.all, R.allPass, R.both, R.either and R.complement

• 0.8.4 Learning to run yarn test before yarn publish the hard way

• 0.8.3 Add R.always, R.T and R.F

• 0.8.2 Add concat, padStart, padEnd, lastIndexOf, toString, reverse, endsWith and startsWith methods

• 0.8.1 Add R.ifElse

• 0.8.0 Add R.not, R.includes | Take string as condition for R.pick and R.omit

• 0.7.6 Fix incorrect implementation of R.values

• 0.7.5 Fix incorrect implementation of R.omit

• 0.7.4 issue #13 - Fix R.curry, which used to return incorrectly function when called with more arguments

• 0.7.3 Close issue #9 - Compile to es2015; Approve PR #10 - add R.addIndex to the API

• 0.7.2 Add Promise support for R.type

• 0.7.1 Close issue #7 - add R.reduce to the API

• 0.7.0 Close issue #5 - change name of curry to partialCurry; add new method curry, which works just like Ramda's curry

• 0.6.2 Add separate documentation site via docsify

Additional info

Running benchmarks

• To run all benchmarks

yarn run benchmark all

• To run single or number of benchmarks

yarn run benchmark add compose filter

Projects using Rambda

• string-fn

• tachyons-for-js

• react-append-to-body

• docker-voting-app-nodejs

• ig-api

• ldap-authenticate

• mat-che

Projects using Rambdax

• WatermelonDB

Rambda in the wild

• Interview with Dejan Totef at SurviveJS blog

• Argumentation of Rambda's curry method

• Trending in Javascripting.com list:

Links to Rambda

• (https://mailchi.mp/webtoolsweekly/web-tools-280)[Web Tools Weekly]

• (https://github.com/stoeffel/awesome-fp-js)[awesome-fp-js]

• (https://github.com/docsifyjs/awesome-docsify)[awesome-docsify]

Browse by category

Function

always

compose

curry

F

flip

identity

pipe

T

tap

Math

add

dec

divide

inc

modulo

multiply

subtract

List

adjust

all

any

append

concat

contains

drop

dropLast

endsWith

filter

find

findIndex

flatten

forEach

groupBy

head

indexBy

indexOf

init

join

last

lastIndexOf

length

map

none

nth

pluck

prepend

range

reduce

reject

repeat

reverse

sort

splitEvery

startsWith

tail

take

takeLast

times

uniq

uniqWith

update

without

zipObj

Logic

allPass

anyPass

both

complement

defaultTo

either

ifElse

not

Object

assoc

dissoc

has

keys

merge

omit

path

pathOr

pick

pickAll

prop

values

Relation

equals

max

maxBy

min

minBy

propEq

sortBy

Type

is

isNil

type

String

match

replace

split

toLower

toString

toUpper

trim