53 lines
2.2 KiB
TypeScript
53 lines
2.2 KiB
TypeScript
import { Notification } from '../Notification';
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import { OperatorFunction } from '../types';
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/**
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* Represents all of the notifications from the source Observable as `next`
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* emissions marked with their original types within {@link Notification}
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* objects.
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*
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* <span class="informal">Wraps `next`, `error` and `complete` emissions in
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* {@link Notification} objects, emitted as `next` on the output Observable.
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* </span>
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*
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* ![](materialize.png)
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*
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* `materialize` returns an Observable that emits a `next` notification for each
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* `next`, `error`, or `complete` emission of the source Observable. When the
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* source Observable emits `complete`, the output Observable will emit `next` as
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* a Notification of type "complete", and then it will emit `complete` as well.
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* When the source Observable emits `error`, the output will emit `next` as a
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* Notification of type "error", and then `complete`.
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*
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* This operator is useful for producing metadata of the source Observable, to
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* be consumed as `next` emissions. Use it in conjunction with
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* {@link dematerialize}.
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*
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* ## Example
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* Convert a faulty Observable to an Observable of Notifications
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* ```ts
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* import { of } from 'rxjs';
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* import { materialize, map } from 'rxjs/operators';
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*
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* const letters = of('a', 'b', 13, 'd');
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* const upperCase = letters.pipe(map(x => x.toUpperCase()));
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* const materialized = upperCase.pipe(materialize());
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* materialized.subscribe(x => console.log(x));
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*
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* // Results in the following:
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* // - Notification {kind: "N", value: "A", error: undefined, hasValue: true}
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* // - Notification {kind: "N", value: "B", error: undefined, hasValue: true}
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* // - Notification {kind: "E", value: undefined, error: TypeError:
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* // x.toUpperCase is not a function at MapSubscriber.letters.map.x
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* // [as project] (http://1…, hasValue: false}
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* ```
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*
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* @see {@link Notification}
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* @see {@link dematerialize}
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*
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* @return {Observable<Notification<T>>} An Observable that emits
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* {@link Notification} objects that wrap the original emissions from the source
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* Observable with metadata.
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* @method materialize
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* @owner Observable
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*/
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export declare function materialize<T>(): OperatorFunction<T, Notification<T>>;
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