emonkak / js-enumerable

A implementation of LINQ to Object for JavaScript that provides the individual methods as a module

@emonkak/enumerable

This library provides the individual methods of LINQ as a module.

Example

import select from '@emonkak/enumerable/select';

Array.from(select.call([1, 2, 3], (x) => x * 2));  // => [2, 4, 6]

You can use method chain by using This-Binding Syntax.

import select from '@emonkak/enumerable/select';
import where from '@emonkak/enumerable/where';
import toArray from '@emonkak/enumerable/toArray';

[1, 2, 3]
    ::where((x) => x % 2 === 0)
    ::select((x) => x * 2)
    ::toArray();  // => [4]

But This-Binding Syntax is still in a proposal yet. So you can not use this without transpiring.

You can use the extension modules instead of this. The extension modules add the method to Enumerable class.

import Enumerable from '@emonkak/enumerable';

import '@emonkak/enumerable/extensions/select';
import '@emonkak/enumerable/extensions/where';
import '@emonkak/enumerable/extensions/toArray';

new Enumerable([1, 2, 3])
    .where((x) => x % 2 === 0)
    .select((x) => x * 2)
    .toArray();  // => [4]

You can also use the HOF(higher-order function) modules.

The HOF modules provides the function that returns the function that receives the Enumerable and returns the result. This function can uses by pipe() and let() method of Enumerable.

import Enumerable from '@emonkak/enumerable';

import select from '@emonkak/enumerable/hof/select';
import where from '@emonkak/enumerable/hof/where';
import toArray from '@emonkak/enumerable/hof/toArray';

new Enumerable([1, 2, 3])
    .pipe(
        where((x) => x % 2 === 0),
        select((x) => x * 2)
    )
    .let(toArray());  // => [4]

API

• aggregate<TSource, TAccumulate>(this: Iterable<TSource>, seed: TAccumulate, func: (result: TAccumulate, element: TSource) => TAccumulate): TAccumulate
• all<TSource>(this: Iterable<TSource>, predicate?: (element: TSource) => boolean): boolean
• any<TSource>(this: Iterable<TSource>, predicate?: (element: TSource) => boolean): boolean
• average<TSource>(this: Iterable<TSource>, selector?: (element: TSource) => number): number
• buffer<TSource>(this: Iterable<TSource>, count: number, skip?: number): Iterable<TSource[]>
• catch<TSource, TException>(this: Iterable<TSource>, handler: (exception: TException) => Iterable<TSource>): Iterable<TSource>
• concat<TSource>(this: Iterable<TSource>, second: Iterable<TSource>): Iterable<TSource>
• count<TSource>(this: Iterable<TSource>, predicate?: (item: TSource) => boolean): number
• defaultIfEmpty<TSource>(this: Iterable<TSource>, defaultValue: TSource): Iterable<TSource>
• distinct<TSource>(this: Iterable<TSource>): Iterable<TSource>
• distinctUntilChanged<TSource>(this: Iterable<TSource>): Iterable<TSource>
• do<TSource>(this: Iterable<TSource>, action: (element: TSource) => void): Iterable<TSource>
• doWhile<TSource>(this: Iterable<TSource>, condition: () => boolean): Iterable<TSource>
• elementAt<TSource>(this: Iterable<TSource>, index: number): TSource
• elementAtOrDefault<TSource>(this: Iterable<TSource>, index: number): TSource | null
• elementAtOrDefault<TSource>(this: Iterable<TSource>, index: number, defaultValue: TSource): TSource
• except<TSource>(this: Iterable<TSource>, second: Iterable<TSource>): Iterable<TSource>
• finally<TSource>(this: Iterable<TSource>, finallyAction: () => void): Iterable<TSource>
• first<TSource>(this: Iterable<TSource>, predicate?: (element: TSource) => boolean): TSource
• firstOrDefault<TSource>(this: Iterable<TSource>): TSource | null
• firstOrDefault<TSource>(this: Iterable<TSource>, predicate: (element: TSource) => boolean): TSource | null
• firstOrDefault<TSource>(this: Iterable<TSource>, predicate: ((element: TSource) => boolean) | null, defaultValue: TSource): TSource
• forEach<TSource>(this: Iterable<TSource>, action: (element: TSource) => void): void
• groupBy<TSource, TKey>(this: Iterable<TSource>, keySelector: (element: TSource) => TKey): Iterable<[TKey, TSource]>
• groupBy<TSource, TKey, TElement>(this: Iterable<TSource>, keySelector: (element: TSource) => TKey, elementSelector: (element: TSource) => TElement): Iterable<[TKey, TElement]>
• groupJoin<TOuter, TInner, TKey, TResult>(this: Iterable<TOuter>, inner: Iterable<TInner>, outerKeySelector: (element: TOuter) => TKey, innerKeySelector: (element: TInner) => TKey, resultSelector: (outer: TOuter, inner: TInner[]) => TResult): Iterable<TResult>
• ignoreElements<TSource>(this: Iterable<TSource>): Iterable<TSource>
• intersect<TSource>(this: Iterable<TSource>, second: Iterable<TSource>): Iterable<TSource>
• isEmpty<TSource>(this: Iterable<TSource>): boolean
• join<TOuter, TInner, TKey, TResult>(this: Iterable<TOuter>, inner: Iterable<TInner>, outerKeySelector: (element: TOuter) => TKey, innerKeySelector: (element: TInner) => TKey, resultSelector: (outer: TOuter, inner: TInner) => TResult): Iterable<TResult>
• last<TSource>(this: Iterable<TSource>, predicate?: (value: TSource) => boolean): TSource
• lastOrDefault<TSource>(this: Iterable<TSource>): TSource | null
• lastOrDefault<TSource>(this: Iterable<TSource>, predicate: (value: TSource) => boolean): TSource | null
• lastOrDefault<TSource>(this: Iterable<TSource>, predicate: ((value: TSource) => boolean) | null, defaultValue: TSource): TSource
• max<TSource>(this: Iterable<TSource>, selector?: (element: TSource) => number): number
• maxBy<TSource, TKey>(this: Iterable<TSource>, keySelector: (element: TSource) => TKey): TSource[]
• memoize<TSource>(this: Iterable<TSource>): Iterable<TSource>
• min<TSource>(this: Iterable<TSource>, selector?: (element: TSource) => number): number
• minBy<TSource, TKey>(this: Iterable<TSource>, keySelector: (element: TSource) => TKey): TSource[]
• onErrorResumeNext<TSource>(this: Iterable<TSource>, second: Iterable<TSource>): Iterable<TSource>
• orderBy<TSource>(this: Iterable<TSource>): OrderedEnumerable<TSource, TSource>
• orderByDescending<TSource>(this: Iterable<TSource>): OrderedEnumerable<TSource, TSource>
• repeat<TSource>(this: Iterable<TSource>, count?: number): Iterable<TSource>
• retry<TSource>(this: Iterable<TSource>, retryCount?: number): Iterable<TSource>
• reverse<TSource>(this: Iterable<TSource>): Iterable<TSource>
• scan<TSource, TAccumulate>(this: Iterable<TSource>, seed: TAccumulate, func: (result: TAccumulate, element: TSource) => TAccumulate): Iterable<TAccumulate>
• select<TSource, TResult>(this: Iterable<TSource>, selector: (element: TSource) => TResult): Iterable<TResult>
• selectMany<TSource, TResult>(this: Iterable<TSource>, collectionSelector: (element: TSource) => Iterable<TResult>): Iterable<TResult>
• single<TSource>(this: Iterable<TSource>, predicate?: (element: TSource) => boolean): TSource
• singleOrDefault<TSource>(this: Iterable<TSource>): TSource | null
• singleOrDefault<TSource>(this: Iterable<TSource>, predicate: (element: TSource) => boolean): TSource | null
• singleOrDefault<TSource>(this: Iterable<TSource>, predicate: ((element: TSource) => boolean) | null, defaultValue: TSource): TSource
• skip<TSource>(this: Iterable<TSource>, count: number): Iterable<TSource>
• skipLast<TSource>(this: Iterable<TSource>, count: number): Iterable<TSource>
• skipWhile<TSource>(this: Iterable<TSource>, predicate: (element: TSource) => boolean): Iterable<TSource>
• startWith<TSource>(this: Iterable<TSource>, ...elements: TSource[]): Iterable<TSource>
• sum<TSource>(this: Iterable<TSource>, selector?: (element: TSource) => number): number
• take<TSource>(this: Iterable<TSource>, count: number): Iterable<TSource>
• takeLast<TSource>(this: Iterable<TSource>, count: number): Iterable<TSource>
• takeWhile<TSource>(this: Iterable<TSource>, predicate: (element: TSource) => boolean): Iterable<TSource>
• toArray<TSource>(this: Iterable<TSource>): TSource[]
• toDictionary<TSource, TKey>(this: Iterable<TSource>, keySelector: (element: TSource) => TKey): Map<TKey, TSource>
• toLookup<TSource, TKey>(this: Iterable<TSource>, keySelector: (element: TSource) => TKey): Map<TKey, TSource[]>
• toObject<TSource>(this: Iterable<TSource>, keySelector: (element: TSource) => string): { [key: string]: TSource; }
• union<TSource>(this: Iterable<TSource>, second: Iterable<TSource>): Iterable<TSource>
• where<TSource>(this: Iterable<TSource>, predicate: (item: TSource) => boolean): Iterable<TSource>
• while<TSource>(this: Iterable<TSource>, condition: () => boolean): Iterable<TSource>
• zip<TFirst, TSecond, TResult>(this: Iterable<TFirst>, second: Iterable<TSecond>, resultSelector: (first: TFirst, second: TSecond) => TResult): Iterable<TResult>