113 lines
4.4 KiB
JavaScript
113 lines
4.4 KiB
JavaScript
import { isArray } from '../util/isArray';
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import { isArrayLike } from '../util/isArrayLike';
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import { isPromise } from '../util/isPromise';
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import { PromiseObservable } from './PromiseObservable';
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import { IteratorObservable } from './IteratorObservable';
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import { ArrayObservable } from './ArrayObservable';
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import { ArrayLikeObservable } from './ArrayLikeObservable';
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import { iterator as Symbol_iterator } from '../symbol/iterator';
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import { Observable } from '../Observable';
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import { ObserveOnSubscriber } from '../operators/observeOn';
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import { observable as Symbol_observable } from '../symbol/observable';
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/**
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* We need this JSDoc comment for affecting ESDoc.
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* @extends {Ignored}
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* @hide true
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*/
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export class FromObservable extends Observable {
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constructor(ish, scheduler) {
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super(null);
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this.ish = ish;
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this.scheduler = scheduler;
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}
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/**
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* Creates an Observable from an Array, an array-like object, a Promise, an
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* iterable object, or an Observable-like object.
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*
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* <span class="informal">Converts almost anything to an Observable.</span>
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*
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* <img src="./img/from.png" width="100%">
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*
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* Convert various other objects and data types into Observables. `from`
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* converts a Promise or an array-like or an
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* [iterable](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Iteration_protocols#iterable)
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* object into an Observable that emits the items in that promise or array or
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* iterable. A String, in this context, is treated as an array of characters.
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* Observable-like objects (contains a function named with the ES2015 Symbol
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* for Observable) can also be converted through this operator.
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*
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* @example <caption>Converts an array to an Observable</caption>
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* var array = [10, 20, 30];
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* var result = Rx.Observable.from(array);
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* result.subscribe(x => console.log(x));
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*
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* // Results in the following:
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* // 10 20 30
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*
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* @example <caption>Convert an infinite iterable (from a generator) to an Observable</caption>
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* function* generateDoubles(seed) {
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* var i = seed;
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* while (true) {
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* yield i;
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* i = 2 * i; // double it
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* }
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* }
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*
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* var iterator = generateDoubles(3);
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* var result = Rx.Observable.from(iterator).take(10);
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* result.subscribe(x => console.log(x));
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*
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* // Results in the following:
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* // 3 6 12 24 48 96 192 384 768 1536
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*
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* @see {@link create}
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* @see {@link fromEvent}
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* @see {@link fromEventPattern}
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* @see {@link fromPromise}
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*
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* @param {ObservableInput<T>} ish A subscribable object, a Promise, an
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* Observable-like, an Array, an iterable or an array-like object to be
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* converted.
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* @param {Scheduler} [scheduler] The scheduler on which to schedule the
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* emissions of values.
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* @return {Observable<T>} The Observable whose values are originally from the
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* input object that was converted.
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* @static true
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* @name from
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* @owner Observable
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*/
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static create(ish, scheduler) {
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if (ish != null) {
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if (typeof ish[Symbol_observable] === 'function') {
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if (ish instanceof Observable && !scheduler) {
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return ish;
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}
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return new FromObservable(ish, scheduler);
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}
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else if (isArray(ish)) {
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return new ArrayObservable(ish, scheduler);
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}
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else if (isPromise(ish)) {
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return new PromiseObservable(ish, scheduler);
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}
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else if (typeof ish[Symbol_iterator] === 'function' || typeof ish === 'string') {
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return new IteratorObservable(ish, scheduler);
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}
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else if (isArrayLike(ish)) {
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return new ArrayLikeObservable(ish, scheduler);
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}
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}
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throw new TypeError((ish !== null && typeof ish || ish) + ' is not observable');
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}
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/** @deprecated internal use only */ _subscribe(subscriber) {
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const ish = this.ish;
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const scheduler = this.scheduler;
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if (scheduler == null) {
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return ish[Symbol_observable]().subscribe(subscriber);
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}
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else {
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return ish[Symbol_observable]().subscribe(new ObserveOnSubscriber(subscriber, scheduler, 0));
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}
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}
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}
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//# sourceMappingURL=FromObservable.js.map
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