Adds ofEntries, ofKeys and ofValues to Iterable/AsyncIterable

ofentries.ts

'use strict';

import { IterableX } from '../iterable';
import { map } from './map';

function makeTuple<TFirst, TSecond>(x: TFirst, y: TSecond): [TFirst, TSecond] {
  return [x, y];
}

class OfEntriesIterable<TSource> extends IterableX<[string, TSource]> {
  private _source: { [key: string]: TSource };

  constructor(source: { [key: string]: TSource }) {
    super();
    this._source = source;
  }

  [Symbol.iterator]() {
    return map(Object.keys(this._source), key => makeTuple(key, this._source[key]))[Symbol.iterator]();
  }
}

export function ofEntries<TSource>(source: { [key: string]: TSource }): IterableX<[string, TSource]> {
  return new OfEntriesIterable<TSource>(source);
}

ofkeys.ts

'use strict';

import { IterableX } from '../iterable';

class OfKeysIterable<TSource> extends IterableX<string> {
  private _source: { [key: string]: TSource };

  constructor(source: { [key: string]: TSource }) {
    super();
    this._source = source;
  }

  [Symbol.iterator]() {
    return Object.keys(this._source)[Symbol.iterator]();
  }
}

export function ofKeys<TSource>(source: { [key: string]: TSource }): IterableX<string> {
  return new OfKeysIterable<TSource>(source);
}

ofvalues.ts

'use strict';

import { IterableX } from '../iterable';
import { map } from './map';

class OfValuesIterable<TSource> extends IterableX<TSource> {
  private _source: { [key: string]: TSource };

  constructor(source: { [key: string]: TSource }) {
    super();
    this._source = source;
  }

  [Symbol.iterator]() {
    return map(Object.keys(this._source), key => this._source[key])[Symbol.iterator]();
  }
}

export function ofValues<TSource>(source: { [key: string]: TSource }): IterableX<TSource> {
  return new OfValuesIterable<TSource>(source);
}