| 1 |
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| 2 | import { Observable, ObservableInput } from 'rxjs';
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| 3 | import { catchError as higherOrder } from 'rxjs/operators';
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| 4 |
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| 5 | /**
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| 6 | * Catches errors on the observable to be handled by returning a new observable or throwing an error.
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| 7 | *
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| 8 | * <img src="./img/catch.png" width="100%">
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| 9 | *
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| 10 | * @example <caption>Continues with a different Observable when there's an error</caption>
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| 11 | *
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| 12 | * Observable.of(1, 2, 3, 4, 5)
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| 13 | * .map(n => {
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| 14 | * if (n == 4) {
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| 15 | * throw 'four!';
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| 16 | * }
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| 17 | * return n;
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| 18 | * })
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| 19 | * .catch(err => Observable.of('I', 'II', 'III', 'IV', 'V'))
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| 20 | * .subscribe(x => console.log(x));
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| 21 | * // 1, 2, 3, I, II, III, IV, V
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| 22 | *
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| 23 | * @example <caption>Retries the caught source Observable again in case of error, similar to retry() operator</caption>
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| 24 | *
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| 25 | * Observable.of(1, 2, 3, 4, 5)
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| 26 | * .map(n => {
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| 27 | * if (n === 4) {
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| 28 | * throw 'four!';
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| 29 | * }
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| 30 | * return n;
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| 31 | * })
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| 32 | * .catch((err, caught) => caught)
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| 33 | * .take(30)
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| 34 | * .subscribe(x => console.log(x));
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| 35 | * // 1, 2, 3, 1, 2, 3, ...
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| 36 | *
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| 37 | * @example <caption>Throws a new error when the source Observable throws an error</caption>
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| 38 | *
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| 39 | * Observable.of(1, 2, 3, 4, 5)
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| 40 | * .map(n => {
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| 41 | * if (n == 4) {
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| 42 | * throw 'four!';
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| 43 | * }
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| 44 | * return n;
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| 45 | * })
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| 46 | * .catch(err => {
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| 47 | * throw 'error in source. Details: ' + err;
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| 48 | * })
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| 49 | * .subscribe(
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| 50 | * x => console.log(x),
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| 51 | * err => console.log(err)
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| 52 | * );
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| 53 | * // 1, 2, 3, error in source. Details: four!
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| 54 | *
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| 55 | * @param {function} selector a function that takes as arguments `err`, which is the error, and `caught`, which
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| 56 | * is the source observable, in case you'd like to "retry" that observable by returning it again. Whatever observable
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| 57 | * is returned by the `selector` will be used to continue the observable chain.
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| 58 | * @return {Observable} An observable that originates from either the source or the observable returned by the
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| 59 | * catch `selector` function.
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| 60 | * @method catch
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| 61 | * @name catch
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| 62 | * @owner Observable
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| 63 | */
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| 64 | export function _catch<T, R>(this: Observable<T>, selector: (err: any, caught: Observable<T>) => ObservableInput<R>): Observable<T | R> {
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| 65 | return higherOrder(selector)(this);
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| 66 | }
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