import { Operator } from '../Operator';
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import { Subscriber } from '../Subscriber';
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import { Observable } from '../Observable';
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import { MonoTypeOperatorFunction, PartialObserver, TeardownLogic } from '../types';
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import { noop } from '../util/noop';
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import { isFunction } from '../util/isFunction';
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/* tslint:disable:max-line-length */
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/** @deprecated Use an observer instead of a complete callback */
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export function tap<T>(next: null | undefined, error: null | undefined, complete: () => void): MonoTypeOperatorFunction<T>;
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/** @deprecated Use an observer instead of an error callback */
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export function tap<T>(next: null | undefined, error: (error: any) => void, complete?: () => void): MonoTypeOperatorFunction<T>;
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/** @deprecated Use an observer instead of a complete callback */
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export function tap<T>(next: (value: T) => void, error: null | undefined, complete: () => void): MonoTypeOperatorFunction<T>;
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export function tap<T>(next?: (x: T) => void, error?: (e: any) => void, complete?: () => void): MonoTypeOperatorFunction<T>;
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export function tap<T>(observer: PartialObserver<T>): MonoTypeOperatorFunction<T>;
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/* tslint:enable:max-line-length */
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/**
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* Perform a side effect for every emission on the source Observable, but return
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* an Observable that is identical to the source.
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*
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* <span class="informal">Intercepts each emission on the source and runs a
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* function, but returns an output which is identical to the source as long as errors don't occur.</span>
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*
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* 
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*
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* Returns a mirrored Observable of the source Observable, but modified so that
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* the provided Observer is called to perform a side effect for every value,
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* error, and completion emitted by the source. Any errors that are thrown in
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* the aforementioned Observer or handlers are safely sent down the error path
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* of the output Observable.
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*
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* This operator is useful for debugging your Observables for the correct values
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* or performing other side effects.
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*
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* Note: this is different to a `subscribe` on the Observable. If the Observable
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* returned by `tap` is not subscribed, the side effects specified by the
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* Observer will never happen. `tap` therefore simply spies on existing
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* execution, it does not trigger an execution to happen like `subscribe` does.
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*
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* ## Example
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* Map every click to the clientX position of that click, while also logging the click event
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* ```ts
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* import { fromEvent } from 'rxjs';
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* import { tap, map } from 'rxjs/operators';
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*
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* const clicks = fromEvent(document, 'click');
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* const positions = clicks.pipe(
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* tap(ev => console.log(ev)),
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* map(ev => ev.clientX),
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* );
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* positions.subscribe(x => console.log(x));
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* ```
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*
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* @see {@link map}
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* @see {@link Observable#subscribe}
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*
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* @param {Observer|function} [nextOrObserver] A normal Observer object or a
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* callback for `next`.
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* @param {function} [error] Callback for errors in the source.
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* @param {function} [complete] Callback for the completion of the source.
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* @return {Observable} An Observable identical to the source, but runs the
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* specified Observer or callback(s) for each item.
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* @name tap
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*/
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export function tap<T>(nextOrObserver?: PartialObserver<T> | ((x: T) => void),
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error?: (e: any) => void,
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complete?: () => void): MonoTypeOperatorFunction<T> {
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return function tapOperatorFunction(source: Observable<T>): Observable<T> {
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return source.lift(new DoOperator(nextOrObserver, error, complete));
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};
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}
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class DoOperator<T> implements Operator<T, T> {
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constructor(private nextOrObserver?: PartialObserver<T> | ((x: T) => void),
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private error?: (e: any) => void,
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private complete?: () => void) {
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}
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call(subscriber: Subscriber<T>, source: any): TeardownLogic {
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return source.subscribe(new TapSubscriber(subscriber, this.nextOrObserver, this.error, this.complete));
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}
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}
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/**
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* We need this JSDoc comment for affecting ESDoc.
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* @ignore
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* @extends {Ignored}
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*/
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class TapSubscriber<T> extends Subscriber<T> {
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private _context: any;
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private _tapNext: ((value: T) => void) = noop;
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private _tapError: ((err: any) => void) = noop;
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private _tapComplete: (() => void) = noop;
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constructor(destination: Subscriber<T>,
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observerOrNext?: PartialObserver<T> | ((value: T) => void),
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error?: (e?: any) => void,
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complete?: () => void) {
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super(destination);
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this._tapError = error || noop;
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this._tapComplete = complete || noop;
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if (isFunction(observerOrNext)) {
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this._context = this;
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this._tapNext = observerOrNext;
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} else if (observerOrNext) {
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this._context = observerOrNext;
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this._tapNext = observerOrNext.next || noop;
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this._tapError = observerOrNext.error || noop;
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this._tapComplete = observerOrNext.complete || noop;
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}
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}
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_next(value: T) {
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try {
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this._tapNext.call(this._context, value);
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} catch (err) {
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this.destination.error(err);
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return;
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}
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this.destination.next(value);
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}
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_error(err: any) {
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try {
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this._tapError.call(this._context, err);
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} catch (err) {
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this.destination.error(err);
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return;
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}
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this.destination.error(err);
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}
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_complete() {
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try {
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this._tapComplete.call(this._context, );
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} catch (err) {
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this.destination.error(err);
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return;
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}
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return this.destination.complete();
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}
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}
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