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- import { Subscriber } from '../Subscriber';
- /* tslint:enable:max-line-length */
- /**
- * Perform a side effect for every emission on the source Observable, but return
- * an Observable that is identical to the source.
- *
- * <span class="informal">Intercepts each emission on the source and runs a
- * function, but returns an output which is identical to the source as long as errors don't occur.</span>
- *
- * <img src="./img/do.png" width="100%">
- *
- * Returns a mirrored Observable of the source Observable, but modified so that
- * the provided Observer is called to perform a side effect for every value,
- * error, and completion emitted by the source. Any errors that are thrown in
- * the aforementioned Observer or handlers are safely sent down the error path
- * of the output Observable.
- *
- * This operator is useful for debugging your Observables for the correct values
- * or performing other side effects.
- *
- * Note: this is different to a `subscribe` on the Observable. If the Observable
- * returned by `do` is not subscribed, the side effects specified by the
- * Observer will never happen. `do` therefore simply spies on existing
- * execution, it does not trigger an execution to happen like `subscribe` does.
- *
- * @example <caption>Map every click to the clientX position of that click, while also logging the click event</caption>
- * var clicks = Rx.Observable.fromEvent(document, 'click');
- * var positions = clicks
- * .do(ev => console.log(ev))
- * .map(ev => ev.clientX);
- * positions.subscribe(x => console.log(x));
- *
- * @see {@link map}
- * @see {@link subscribe}
- *
- * @param {Observer|function} [nextOrObserver] A normal Observer object or a
- * callback for `next`.
- * @param {function} [error] Callback for errors in the source.
- * @param {function} [complete] Callback for the completion of the source.
- * @return {Observable} An Observable identical to the source, but runs the
- * specified Observer or callback(s) for each item.
- * @name tap
- */
- export function tap(nextOrObserver, error, complete) {
- return function tapOperatorFunction(source) {
- return source.lift(new DoOperator(nextOrObserver, error, complete));
- };
- }
- class DoOperator {
- constructor(nextOrObserver, error, complete) {
- this.nextOrObserver = nextOrObserver;
- this.error = error;
- this.complete = complete;
- }
- call(subscriber, source) {
- return source.subscribe(new DoSubscriber(subscriber, this.nextOrObserver, this.error, this.complete));
- }
- }
- /**
- * We need this JSDoc comment for affecting ESDoc.
- * @ignore
- * @extends {Ignored}
- */
- class DoSubscriber extends Subscriber {
- constructor(destination, nextOrObserver, error, complete) {
- super(destination);
- const safeSubscriber = new Subscriber(nextOrObserver, error, complete);
- safeSubscriber.syncErrorThrowable = true;
- this.add(safeSubscriber);
- this.safeSubscriber = safeSubscriber;
- }
- _next(value) {
- const { safeSubscriber } = this;
- safeSubscriber.next(value);
- if (safeSubscriber.syncErrorThrown) {
- this.destination.error(safeSubscriber.syncErrorValue);
- }
- else {
- this.destination.next(value);
- }
- }
- _error(err) {
- const { safeSubscriber } = this;
- safeSubscriber.error(err);
- if (safeSubscriber.syncErrorThrown) {
- this.destination.error(safeSubscriber.syncErrorValue);
- }
- else {
- this.destination.error(err);
- }
- }
- _complete() {
- const { safeSubscriber } = this;
- safeSubscriber.complete();
- if (safeSubscriber.syncErrorThrown) {
- this.destination.error(safeSubscriber.syncErrorValue);
- }
- else {
- this.destination.complete();
- }
- }
- }
- //# sourceMappingURL=tap.js.map
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