iterable-operator
Advanced tools
Utilities for JavaScript Iterable and AsyncIterable.
npm install --save iterable-operator
# or
yarn add iterable-operator
import { map, toArray } from 'iterable-operator'
const iter = [1, 2, 3]
const doubleIter = map(iter, x => x * 2)
const result = toArray(doubleIter)
You may need a pipe function.
function isIterable<T>(val: unknown): val is Iterable<T>
function isntIterable<T>(val: T): val is Exclude<T, Iterable<unknown>>
function isAsyncIterable<T>(val: unknown): val is AsyncIterable<T>
function isntAsyncIterable<T>(
val: T
): val is Exclude<T, AsyncIterable<unknown>>
function chunk<T>(
iterable: Iterable<T>
, size: number // size > 0
): IterableIterator<T[]>
function chunkAsync<T>(
iterable: AsyncIterable<T>
, size: number // size > 0
): AsyncIterableIterator<Array<Awaited<T>>>
chunk([1, 2, 3], 2) // [[1, 2], [3]]
chunk([1, 2, 3], 3) // [[1, 2, 3]]
chunk([1, 2, 3], 5) // [[1, 2, 3]]
chunk([1, 2, 3], 0) // throw Error
chunk([1, 2, 3], -1) // throw Error
The memory usage of this function depends on size.
function chunkBy<T>(
iterable: Iterable<T>
, predicate: (element: T, index: number) => unknown
): IterableIterator<T[]>
function chunkByAsync<T>(
iterable: Iterable<T> | AsyncIterable<T>
, predicate: (element: Awaited<T>, index: number) => Awaitable<unknown>
): AsyncIterableIterator<Array<Awaited<T>>>
chunkBy([1, 2, 3], x => x === 2) // [[1, 2], [3]]
chunkBy([1, 2, 3], x => x === 3) // [[1, 2, 3]]
chunkBy([1, 2, 3], x => x === 5) // [[1, 2, 3]]
The memory usage of this function depends on iterable and predicate.
function concat<T, U>(
iterable: Iterable<T>
, ...otherIterables: Iterable<U>[]
): IterableIterator<T | U>
function concatAsync<T, U>(
iterable: Iterable<T> | AsyncIterable<T>
, ...otherIterables: Array<Iterable<Awaitable<U>> | AsyncIterable<Awaitable<U>>>
): AsyncIterableIterator<Awaited<T> | Awaited<U>>
concat([1, 2, 3]) // [1, 2, 3]
concat([1, 2, 3], ['a', 'b', 'c']) // [1, 2, 3, 'a', 'b', 'c']
function difference<T>(left: Iterable<T>, right: Iterable<T>): IterableIterator<T>
function differenceAsync<T>(
left: Iterable<Awaitable<T>> | AsyncIterable<Awaitable<T>>
, right: Iterable<Awaitable<T>> | AsyncIterable<Awaitable<T>>
): AsyncIterableIterator<Awaited<T>>
difference([1, 2, 3], [3, 4, 5]) // [1, 2]
The memory usage of this function depends on right.
function drop<T>(
iterable: Iterable<T>
, count: number // count >= 0
): IterableIterator<T>
function dropAsync<T>(
iterable: AsyncIterable<T>
, count: number // count >= 0
): AsyncIterableIterator<Awaited<T>>
drop([1, 2, 3], 0) // [1, 2, 3]
drop([1, 2, 3], 2) // [3]
drop([1, 2, 3], 3) // []
drop([1, 2, 3], 5) // []
drop([1, 2, 3], -1) // throw Error
function dropRight<T>(
iterable: Iterable<T>
, count: number // count >= 0
): IterableIterator<T>
function dropRightAsync<T>(
iterable: AsyncIterable<T>
, count: number // count >= 0
): AsyncIterableIterator<Awaited<T>>
dropRight([1, 2, 3], 0) // [1, 2, 3]
dropRight([1, 2, 3], 2) // [1]
dropRight([1, 2, 3], 3) // []
dropRight([1, 2, 3], 5) // []
dropRight([1, 2, 3], -1) // throw Error
The memory usage of this function depends on iterable.
function dropUntil<T>(
iterable: Iterable<T>
, predicate: (element: T, index: number) => unknown
): IterableIterator<T>
function dropUntilAsync<T>(
iterable: Iterable<T> | AsyncIterable<T>
, predicate: (element: Awaited<T>, index: number) => Awaitable<unknown>
): AsyncIterableIterator<Awaited<T>>
dropUntil([1, 2, 3], x => x === 2) // [2, 3]
The memory usage of this function depends on iterable and predicate.
function filter<T, U extends T = T>(
iterable: Iterable<T>
, predicate: (element: T, index: number) => unknown
): IterableIterator<U>
function filterAsync<T, U extends Awaited<T> = Awaited<T>>(
iterable: Iterable<T> | AsyncIterable<T>
, predicate: (element: Awaited<T>, index: number) => Awaitable<unknown>
): AsyncIterableIterator<U>
filter([1, 2, 3], x => x % 2 === 1) // [1, 3]
function flatten<T>(iterable: Iterable<unknown>): IterableIterator<T>
function flattenAsync<T>(iterable: AsyncIterable<unknown>): AsyncIterableIterator<T>
flatten([]) // []
flatten('123') // ['1', '2', '3']
flatten(['one', ['two'], 0, [1, [2]]]) // ['o', 'n', 'e', 'two', 0, 1, [2]]
function flattenDeep<T>(
iterable: Iterable<unknown>
, depth: number = Infinity // depth >= 0
): IterableIterator<T>
function flattenDeepAsync<T>(
iterable: AsyncIterable<unknown>
, depth: number = Infinity // depth >= 0
): AsyncIterableIterator<T>
flattenDeep([]) // []
flattenDeep('123') // ['1', '2', '3']
flattenDeep([], -1) // throw Error
flattenDeep([0, [1]], 0) // [0, [1]]
flattenDeep(['one', ['two', ['three']], 0, [1, [2, [3]]]], 2) // ['o', 'n', 'e', 't', 'w', 'o', 'three', 0, 1, 2, [3]]
function flattenBy<T>(
iterable: Iterable<unknown>
, predicate: (element: unknown, level: number) => boolean
): IterableIterator<T>
function flattenByAsync<T>(
iterable: Iterable<unknown> | AsyncIterable<unknown>
, predicate: (element: unknown, level: number) => Awaitable<unknown>
): AsyncIterableIterator<T>
flattenBy(['one', ['two'], 0, [1]], x => typeof x !== 'string') // ['one', 'two', 0, 1]
flattenBy([], () => true) // []
flattenBy('123', () => true) // ['1', '2', '3']
function intersection<T>(left: Iterable<T>, right: Iterable<T>): IterableIterator<T>
function intersectionAsync<T>(
left: Iterable<Awaitable<T>> | AsyncIterable<T>
, right: Iterable<Awaitable<T>> | AsyncIterable<T>
): AsyncIterableIterator<Awaited<T>>
The memory usage of this function depends on right.
intersection([1, 2], [2, 3]) // [2]
function map<T, U>(
iterable: Iterable<T>
, fn: (element: T, index: number) => U
): IterableIterator<U>
function mapAsync<T, U>(
iterable: Iterable<T> | AsyncIterable<T>
, fn: (element: Awaited<T>, index: number) => Awaitable<U>
): AsyncIterableIterator<Awaited<U>>
map([1, 2, 3], x => x * 2) // [2, 4, 6]
function flatMap<T, U>(
iterable: Iterable<T>
, fn: (element: T, index: number) => Iterable<U>
): IterableIterator<U>
function flatMapAsync<T, U>(
iterable: Iterable<T> | AsyncIterable<T>
, fn: (element: Awaited<T>, index: number) => Awaitable<Iterable<U> | AsyncIterable<U>>
): AsyncIterableIterator<Awaited<U>>
map([1, 2, 3], x => [x, x * 2]) // [1, 2, 2, 4, 3, 6]
function repeat<T>(
iterable: Iterable<T>
, times: number // times >= 0
): IterableIterator<T>
function repeatAsync<T>(
iterable: AsyncIterable<T>
, times: number // times >= 0
): AsyncIterableIterator<Awaited<T>>
repeat([1, 2, 3], 2) // [1, 2, 3, 1, 2, 3]
repeat([1, 2, 3], 0) // []
repeat([1, 2, 3], -1) // throw Error
The memory usage of this function depends on iterable.
function slice<T>(
iterable: Iterable<T>
, start: number // start >= 0
, end: number = Infinity // end >= start
): IterableIterator<T>
function sliceAsync<T>(
iterable: AsyncIterable<T>
, start: number // start >= 0
, end: number = Infinity // end >= start
): AsyncIterableIterator<Awaited<T>>
slice([1, 2, 3], -1, 1) // throw Error
slice([1, 2, 3], 3, 5) // []
slice([1, 2, 3], 1, 2) // [2]
slice([1, 2, 3], 1, 1) // []
slice([1, 2, 3], 2, 1) // throw Error
function join<T, U = T>(iterable: Iterable<T>, separator: U): IterableIterator<T | U>
function joinAsync<T, U = T>(
iterable: AsyncIterable<T>
, separator: U
): AsyncIterableIterator<Awaited<T> | U>
join([1, 2, 3], '+') // [1, '+', 2, '+', 3]
function split<T>(iterable: Iterable<T>, separator: T): IterableIterator<T[]>
function splitAsync<T>(
iterable: AsyncIterable<T>
, separator: T
): AsyncIterableIterator<Array<Awaited<T>>>
split([1, 2, 3, 4, 5], 3) // [[1, 2], [4, 5]]
split([1, 2, 3, 4, 5], 1) // [[], [2, 3, 4, 5]]
split([1, 2, 3, 4, 5], 5) // [[1, 2, 3, 4], []]
split([1, 2, 3, 4, 5], 0) // [[1, 2, 3, 4, 5]]
The memory usage of this function depends on iterable and separator.
function splitBy<T>(
iterable: Iterable<T>
, predicate: (element: T, index: number) => unknown
): IterableIterator<T[]>
function splitByAsync<T>(
iterable: Iterable<T> | AsyncIterable<T>
, predicate: (element: Awaited<T>, index: number) => Awaitable<unknown>
): AsyncIterableIterator<Array<Awaited<T>>>
splitBy([1, 2, 3, 4, 5], x => x === 3) // [[1, 2], [4, 5]]
splitBy([1, 2, 3, 4, 5], x => x === 1) // [[], [2, 3, 4, 5]]
splitBy([1, 2, 3, 4, 5], x => x === 5) // [[1, 2, 3, 4], []]
splitBy([1, 2, 3, 4, 5], x => x === 0) // [[1, 2, 3, 4, 5]]
The memory usage of this function depends on iterable and predicate.
function take<T>(iterable: Iterable<T>, count: number): IterableIterator<T>
function takeAsync<T>(
iterable: AsyncIterable<T>
, count: number
): AsyncIterableIterator<Awaited<T>>
take([1, 2, 3], 5) // [1, 2, 3]
take([1, 2, 3], 2) // [1, 2]
take([1, 2, 3], 0) // []
take([1, 2, 3], -1) // throw Error
function takeRight<T>(iterable: Iterable<T>, count: number): IterableIterator<T>
function takeRightAsync<T>(
iterable: AsyncIterable<T>
, count: number
): AsyncIterableIterator<Awaited<T>>
takeRight([1, 2, 3], 2) // [2, 3]
takeRight([1, 2, 3], 5) // [1, 2, 3]
takeRight([1, 2, 3], 0) // []
takeRight([1, 2, 3], -1) // throw Error
The memory usage of this function depends on count.
function takeUntil<T>(
iterable: Iterable<T>
, predicate: (element: T, index: number) => unknown
): IterableIterator<T>
function takeUntilAsync<T>(
iterable: Iterable<T> | AsyncIterable<T>
, predicate: (element: Awaited<T>, index: number) => Awaitable<unknown>
): AsyncIterableIterator<Awaited<T>>
takeUntil([1, 2, 3], x => x === 2) // [1]
function tap<T>(
iterable: Iterable<T>
, fn: (element: T, index: number) => unknown
): IterableIterator<T>
function tapAsync<T>(
iterable: Iterable<T> | AsyncIterable<T>
, fn: (element: Awaited<T>, index: number) => Awaitable<unknown>
): AsyncIterableIterator<Awaited<T>>
tap([1, 2, 3], x => console.log(x)) // [1, 2, 3]
function toAsyncIterable<T>(
iterable: Iterable<Awaitable<T>>
): AsyncIterableIterator<Awaited<T>>
toAsyncIterable([1, 2, 3]) // AsyncIterable [1, 2, 3]
function transform<T, U>(
iterable: Iterable<T>
, transformer: (iterable: Iterable<T>) => Iterable<U>
): IterableIterator<U>
function transformAsync<T, U>(
iterable: Iterable<T>
, transformer: (iterable: Iterable<T>) => AsyncIterable<U>
): AsyncIterableIterator<Awaited<U>>
function transformAsync<T, U>(
iterable: AsyncIterable<T>
, transformer: (iterable: AsyncIterable<T>) => AsyncIterable<U>
): AsyncIterableIterator<Awaited<U>>
transform([1, 2, 3], function* double(iter) {
for (const element of iter) {
yield element * 2
}
}) // [2, 4, 6]
function uniq<T>(iterable: Iterable<T>): IterableIterator<T>
function uniqAsync<T>(iterable: AsyncIterable<T>): AsyncIterableIterator<Awaited<T>>
uniq([1, 1, 2, 2, 3, 3]) // [1, 2, 3]
The memory usage of this function depends on iterable.
function uniqBy<T, U>(
iterable: Iterable<T>
, fn: (element: T, index: number) => U
): IterableIterator<T>
function uniqByAsync<T, U>(
iterable: Iterable<T> | AsyncIterable<T>
, fn: (element: Awaited<T>, index: number) => Awaitable<U>
): AsyncIterableIterator<Awaited<T>>
uniqBy([1, 2, 3], x => x % 2) // [1, 2]
The memory usage of this function depends on fn.
function zip<T, U extends Array<Iterable<unknown>>>(
iterable: Iterable<T>
, ...otherIterables: U
): IterableIterator<[T, ...ExtractTypeTupleFromIterableTuple<U>]>
function zipAsync<
T
, U extends Array<Iterable<Awaitable<unknown>> | AsyncIterable<Awaitable<unknown>>>
>(
iterable: Iterable<Awaitable<T>> | AsyncIterable<Awaitable<T>>
, ...otherIterables: U
): AsyncIterableIterator<
[Awaited<T>, ...ExtractTypeTupleFromAsyncLikeIterableTuple<U>]
>
zip([1, 2, 3], ['a', 'b', 'c']) // [[1, 'a'], [2, 'b'], [3, 'c']]
zip([1, 2, 3], ['a', 'b']) // [[1, 'a'], [2, 'b']
zip([1, 2, 3], ['a', 'b'], ['i', 'ii', 'iii']) // [[1, 'a', 'i'], [2, 'b', 'ii']]
function consume<T, U>(iterable: Iterable<T>, consumer: (iterable: Iterable<T>) => U): U
function consumeAsync<T, U>(
iterable: Iterable<T>
, consumer: (iterable: Iterable<T>) => Awaitable<U>
): Promise<Awaited<U>>
function consumeAsync<T, U>(
iterable: AsyncIterable<T>
, consumer: (iterable: AsyncIterable<T>) => Awaitable<U>
): Promise<Awaited<U>>
consume([1, 2, 3], xs => new Set(xs)) // Set [1, 2, 3]
function each<T>(
iterable: Iterable<T>
, fn: (element: T, index: number) => unknown
): void
function eachAsync<T>(
iterable: Iterable<T> | AsyncIterable<T>
, fn: (element: Awaited<T>, index: number) => Awaitable<unknown>
): Promise<void>
each([1, 2, 3], x => console.log(x)) // void
function every<T>(
iterable: Iterable<T>
, predicate: (element: T, index: number) => unknown
): boolean
function everyAsync<T>(
iterable: Iterable<T> | AsyncIterable<T>
, predicate: (element: Awaited<T>, index: number) => Awaitable<unknown>
): Promise<boolean>
every([1, 2, 3], x => x < 5) // true
every([1, 2, 3], x => x <= 2) // false
function find<T>(
iterable: Iterable<T>
, predicate: (element: T, index: number) => unknown
): T | undefined
function findAsync<T>(
iterable: Iterable<T> | AsyncIterable<T>
, predicate: (element: Awaited<T>, index: number) => Awaitable<unknown>
): Promise<Awaited<T> | undefined>
find([1, 2, 3], x => x === 2) // 2
find([1, 2, 3], x => x === 4) // undefined
function findAllIndexes<T>(
iterable: Iterable<T>
, predicate: (value: T, index: number) => unknown
): IterableIterator<number>
findAllIndexes([1, 2, 3], x => x % 2 === 1) // [0, 2]
function first<T>(iterable: Iterable<T>): T | undefined
function firstAsync<T>(iterable: AsyncIterable<T>): Promise<Awaited<T> | undefined>
first([1, 2, 3]) // 1
first([]) // undefined
function includes<T>(iterable: Iterable<T>, value: T): boolean
function includesAsync<T>(
iterable: AsyncIterable<T>
, value: Awaited<T>
): Promise<boolean>
includes([1, 2, 3], 2) // true
includes([1, 2, 3], 4) // false
function last<T>(iterable: Iterable<T>): T | undefined
function lastAsync<T>(iterable: AsyncIterable<T>): Promise<Awaited<T> | undefined>
last([1, 2, 3]) // 3
last([]) // undefined
function reduce<T>(
iterable: Iterable<T>
, fn: (accumulator: T, currentValue: T, index: number) => T
): T
function reduce<T, U>(
iterable: Iterable<T>
, fn: (accumulator: U, currentValue: T, index: number) => U
, initialValue: U
): U
function reduceAsync<T>(
iterable: Iterable<T> | AsyncIterable<T>
, fn: (
accumulator: Awaited<T>
, currentValue: Awaited<T>
, index: number
) => Awaitable<Awaited<T>>
): Promise<Awaited<T>>
function reduceAsync<T, U>(
iterable: Iterable<T> | AsyncIterable<T>
, fn: (accumulator: Awaited<U>, currentValue: Awaited<T>, index: number) => Awaitable<U>
, initialValue: U
): Promise<Awaited<U>>
reduce([], (acc, cur) => acc + cur) // throw Error
reduce([1], (acc, cur) => acc + cur) // 1
reduce([1, 2, 3], (acc, cur) => acc + cur) // 6
reduce([1, 2, 3], (acc, cur, index) => {
acc.push([cur, index])
return acc
}) // [[1, 0], [2, 1], [3, 2]]
function some<T>(
iterable: Iterable<T>
, predicate: (element: T, index: number) => unknown
): boolean
function someAsync<T>(
iterable: Iterable<T> | AsyncIterable<T>
, predicate: (element: Awaited<T>, index: number) => Awaitable<unknown>
): Promise<boolean>
some([1, 2, 3], x => x === 2) // true
some([1, 2, 3], x => x === 4) // false
function toArray<T>(iterable: Iterable<T>): T[]
function toArrayAsync<T>(
iterable: AsyncIterable<T>
): Promise<Array<Awaited<T>>>
toArray([1, 2, 3]) // Array [1, 2, 3]
function toSet<T>(iterable: Iterable<T>): Set<T>
function toSetAsync<T>(
iterable: Iterable<T> | AsyncIterable<T>
): Promise<Set<Awaited<T>>>
toSet([1, 1, 2, 2, 3, 3]) // Set [1, 2, 3]
function count(iterable: Iterable<unknown>): number
function countAsync(iterable: AsyncIterable<unknown>): Promise<number>
count([1, 2, 3]) // 3
function groupBy<T, U>(
iterable: Iterable<T>
, fn: (element: T, index: number) => U
): Map<U, T[]>
function groupByAsync<T, U>(
iterable: Iterable<T> | AsyncIterable<T>
, fn: (element: Awaited<T>, index: number) => Awaitable<U>
): Promise<Map<Awaited<U>, Array<Awaited<T>>>>
groupBy([1, 2, 3], x => x % 2) // { 1: [1, 3], 0: [2] }
function prefetch<T>(iterable: Iterable<T>, size: number): AsyncIterableIterator<T>
function prefetchAsync<T>(
iterable: AsyncIterable<T>
, size: number
): AsyncIterableIterator<T>
function top<T>(
iterable: Iterable<T>
, num: number
, compare: (a: T, b: T) => number
): T[]
function topAsync<T>(
iterable: AsyncIterable<T>
, num: number
, compare: (a: Awaited<T>, b: Awaited<T>) => number
): Promise<Array<Awaited<T>>>
top([1, 2, 3], 2, (a, b) => b - a) // [3, 2]
function avg(iterable: Iterable<number>): number
function avgAsync(iterable: AsyncIterable<number>): Promise<number>
avg([1, 2, 3]) // 2
FAQs
Utilities for JavaScript Iterable and AsyncIterable
We found that iterable-operator 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.
Did you know?
Socket for GitHub automatically highlights issues in each pull request and monitors the health of all your open source dependencies. Discover the contents of your packages and block harmful activity before you install or update your dependencies.
Security News
Research
An advanced npm supply chain attack is leveraging Ethereum smart contracts for decentralized, persistent malware control, evading traditional defenses.
Security News
Research
Attackers are impersonating Sindre Sorhus on npm with a fake 'chalk-node' package containing a malicious backdoor to compromise developers' projects.
Security News
The npm package for the LottieFiles Player web component was hit with a supply chain attack after a software engineer's npmjs credentials were compromised.