work.suroh.tk/node_modules/rxjs/_esm2015/observable/PromiseObservable.js

111 lines
3.9 KiB
JavaScript

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