111 lines
3.9 KiB
JavaScript
111 lines
3.9 KiB
JavaScript
import { root } from '../util/root';
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import { Observable } from '../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 PromiseObservable extends Observable {
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constructor(promise, scheduler) {
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super();
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this.promise = promise;
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this.scheduler = scheduler;
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}
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/**
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* Converts a Promise to an Observable.
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*
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* <span class="informal">Returns an Observable that just emits the Promise's
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* resolved value, then completes.</span>
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*
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* Converts an ES2015 Promise or a Promises/A+ spec compliant Promise to an
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* Observable. If the Promise resolves with a value, the output Observable
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* emits that resolved value as a `next`, and then completes. If the Promise
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* is rejected, then the output Observable emits the corresponding Error.
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*
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* @example <caption>Convert the Promise returned by Fetch to an Observable</caption>
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* var result = Rx.Observable.fromPromise(fetch('http://myserver.com/'));
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* result.subscribe(x => console.log(x), e => console.error(e));
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*
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* @see {@link bindCallback}
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* @see {@link from}
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*
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* @param {PromiseLike<T>} promise The promise to be converted.
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* @param {Scheduler} [scheduler] An optional IScheduler to use for scheduling
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* the delivery of the resolved value (or the rejection).
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* @return {Observable<T>} An Observable which wraps the Promise.
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* @static true
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* @name fromPromise
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* @owner Observable
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*/
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static create(promise, scheduler) {
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return new PromiseObservable(promise, scheduler);
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}
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/** @deprecated internal use only */ _subscribe(subscriber) {
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const promise = this.promise;
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const scheduler = this.scheduler;
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if (scheduler == null) {
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if (this._isScalar) {
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if (!subscriber.closed) {
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subscriber.next(this.value);
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subscriber.complete();
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}
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}
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else {
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promise.then((value) => {
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this.value = value;
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this._isScalar = true;
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if (!subscriber.closed) {
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subscriber.next(value);
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subscriber.complete();
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}
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}, (err) => {
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if (!subscriber.closed) {
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subscriber.error(err);
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}
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})
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.then(null, err => {
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// escape the promise trap, throw unhandled errors
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root.setTimeout(() => { throw err; });
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});
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}
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}
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else {
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if (this._isScalar) {
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if (!subscriber.closed) {
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return scheduler.schedule(dispatchNext, 0, { value: this.value, subscriber });
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}
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}
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else {
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promise.then((value) => {
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this.value = value;
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this._isScalar = true;
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if (!subscriber.closed) {
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subscriber.add(scheduler.schedule(dispatchNext, 0, { value, subscriber }));
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}
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}, (err) => {
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if (!subscriber.closed) {
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subscriber.add(scheduler.schedule(dispatchError, 0, { err, subscriber }));
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}
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})
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.then(null, (err) => {
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// escape the promise trap, throw unhandled errors
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root.setTimeout(() => { throw err; });
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});
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}
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}
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}
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}
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function dispatchNext(arg) {
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const { value, subscriber } = arg;
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if (!subscriber.closed) {
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subscriber.next(value);
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subscriber.complete();
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}
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}
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function dispatchError(arg) {
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const { err, subscriber } = arg;
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if (!subscriber.closed) {
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subscriber.error(err);
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}
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}
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//# sourceMappingURL=PromiseObservable.js.map
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