Opal-Estate-Pro/node_modules/rxjs/_esm2015/operators/onErrorResumeNext.js
2019-09-13 11:27:52 +07:00

118 lines
4.7 KiB
JavaScript
Executable File

import { FromObservable } from '../observable/FromObservable';
import { isArray } from '../util/isArray';
import { OuterSubscriber } from '../OuterSubscriber';
import { subscribeToResult } from '../util/subscribeToResult';
/* tslint:enable:max-line-length */
/**
* When any of the provided Observable emits an complete or error notification, it immediately subscribes to the next one
* that was passed.
*
* <span class="informal">Execute series of Observables no matter what, even if it means swallowing errors.</span>
*
* <img src="./img/onErrorResumeNext.png" width="100%">
*
* `onErrorResumeNext` is an operator that accepts a series of Observables, provided either directly as
* arguments or as an array. If no single Observable is provided, returned Observable will simply behave the same
* as the source.
*
* `onErrorResumeNext` returns an Observable that starts by subscribing and re-emitting values from the source Observable.
* When its stream of values ends - no matter if Observable completed or emitted an error - `onErrorResumeNext`
* will subscribe to the first Observable that was passed as an argument to the method. It will start re-emitting
* its values as well and - again - when that stream ends, `onErrorResumeNext` will proceed to subscribing yet another
* Observable in provided series, no matter if previous Observable completed or ended with an error. This will
* be happening until there is no more Observables left in the series, at which point returned Observable will
* complete - even if the last subscribed stream ended with an error.
*
* `onErrorResumeNext` can be therefore thought of as version of {@link concat} operator, which is more permissive
* when it comes to the errors emitted by its input Observables. While `concat` subscribes to the next Observable
* in series only if previous one successfully completed, `onErrorResumeNext` subscribes even if it ended with
* an error.
*
* Note that you do not get any access to errors emitted by the Observables. In particular do not
* expect these errors to appear in error callback passed to {@link subscribe}. If you want to take
* specific actions based on what error was emitted by an Observable, you should try out {@link catch} instead.
*
*
* @example <caption>Subscribe to the next Observable after map fails</caption>
* Rx.Observable.of(1, 2, 3, 0)
* .map(x => {
* if (x === 0) { throw Error(); }
return 10 / x;
* })
* .onErrorResumeNext(Rx.Observable.of(1, 2, 3))
* .subscribe(
* val => console.log(val),
* err => console.log(err), // Will never be called.
* () => console.log('that\'s it!')
* );
*
* // Logs:
* // 10
* // 5
* // 3.3333333333333335
* // 1
* // 2
* // 3
* // "that's it!"
*
* @see {@link concat}
* @see {@link catch}
*
* @param {...ObservableInput} observables Observables passed either directly or as an array.
* @return {Observable} An Observable that emits values from source Observable, but - if it errors - subscribes
* to the next passed Observable and so on, until it completes or runs out of Observables.
* @method onErrorResumeNext
* @owner Observable
*/
export function onErrorResumeNext(...nextSources) {
if (nextSources.length === 1 && isArray(nextSources[0])) {
nextSources = nextSources[0];
}
return (source) => source.lift(new OnErrorResumeNextOperator(nextSources));
}
/* tslint:enable:max-line-length */
export function onErrorResumeNextStatic(...nextSources) {
let source = null;
if (nextSources.length === 1 && isArray(nextSources[0])) {
nextSources = nextSources[0];
}
source = nextSources.shift();
return new FromObservable(source, null).lift(new OnErrorResumeNextOperator(nextSources));
}
class OnErrorResumeNextOperator {
constructor(nextSources) {
this.nextSources = nextSources;
}
call(subscriber, source) {
return source.subscribe(new OnErrorResumeNextSubscriber(subscriber, this.nextSources));
}
}
class OnErrorResumeNextSubscriber extends OuterSubscriber {
constructor(destination, nextSources) {
super(destination);
this.destination = destination;
this.nextSources = nextSources;
}
notifyError(error, innerSub) {
this.subscribeToNextSource();
}
notifyComplete(innerSub) {
this.subscribeToNextSource();
}
_error(err) {
this.subscribeToNextSource();
}
_complete() {
this.subscribeToNextSource();
}
subscribeToNextSource() {
const next = this.nextSources.shift();
if (next) {
this.add(subscribeToResult(this, next));
}
else {
this.destination.complete();
}
}
}
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