| import { OuterSubscriber } from '../OuterSubscriber'; |
| import { subscribeToResult } from '../util/subscribeToResult'; |
| /** |
| * Catches errors on the observable to be handled by returning a new observable or throwing an error. |
| * |
| * <img src="./img/catch.png" width="100%"> |
| * |
| * @example <caption>Continues with a different Observable when there's an error</caption> |
| * |
| * Observable.of(1, 2, 3, 4, 5) |
| * .map(n => { |
| * if (n == 4) { |
| * throw 'four!'; |
| * } |
| * return n; |
| * }) |
| * .catch(err => Observable.of('I', 'II', 'III', 'IV', 'V')) |
| * .subscribe(x => console.log(x)); |
| * // 1, 2, 3, I, II, III, IV, V |
| * |
| * @example <caption>Retries the caught source Observable again in case of error, similar to retry() operator</caption> |
| * |
| * Observable.of(1, 2, 3, 4, 5) |
| * .map(n => { |
| * if (n === 4) { |
| * throw 'four!'; |
| * } |
| * return n; |
| * }) |
| * .catch((err, caught) => caught) |
| * .take(30) |
| * .subscribe(x => console.log(x)); |
| * // 1, 2, 3, 1, 2, 3, ... |
| * |
| * @example <caption>Throws a new error when the source Observable throws an error</caption> |
| * |
| * Observable.of(1, 2, 3, 4, 5) |
| * .map(n => { |
| * if (n == 4) { |
| * throw 'four!'; |
| * } |
| * return n; |
| * }) |
| * .catch(err => { |
| * throw 'error in source. Details: ' + err; |
| * }) |
| * .subscribe( |
| * x => console.log(x), |
| * err => console.log(err) |
| * ); |
| * // 1, 2, 3, error in source. Details: four! |
| * |
| * @param {function} selector a function that takes as arguments `err`, which is the error, and `caught`, which |
| * is the source observable, in case you'd like to "retry" that observable by returning it again. Whatever observable |
| * is returned by the `selector` will be used to continue the observable chain. |
| * @return {Observable} An observable that originates from either the source or the observable returned by the |
| * catch `selector` function. |
| * @name catchError |
| */ |
| export function catchError(selector) { |
| return function catchErrorOperatorFunction(source) { |
| const operator = new CatchOperator(selector); |
| const caught = source.lift(operator); |
| return (operator.caught = caught); |
| }; |
| } |
| class CatchOperator { |
| constructor(selector) { |
| this.selector = selector; |
| } |
| call(subscriber, source) { |
| return source.subscribe(new CatchSubscriber(subscriber, this.selector, this.caught)); |
| } |
| } |
| /** |
| * We need this JSDoc comment for affecting ESDoc. |
| * @ignore |
| * @extends {Ignored} |
| */ |
| class CatchSubscriber extends OuterSubscriber { |
| constructor(destination, selector, caught) { |
| super(destination); |
| this.selector = selector; |
| this.caught = caught; |
| } |
| // NOTE: overriding `error` instead of `_error` because we don't want |
| // to have this flag this subscriber as `isStopped`. We can mimic the |
| // behavior of the RetrySubscriber (from the `retry` operator), where |
| // we unsubscribe from our source chain, reset our Subscriber flags, |
| // then subscribe to the selector result. |
| error(err) { |
| if (!this.isStopped) { |
| let result; |
| try { |
| result = this.selector(err, this.caught); |
| } |
| catch (err2) { |
| super.error(err2); |
| return; |
| } |
| this._unsubscribeAndRecycle(); |
| this.add(subscribeToResult(this, result)); |
| } |
| } |
| } |
| //# sourceMappingURL=catchError.js.map |