103 lines
3.8 KiB
JavaScript
Executable File
103 lines
3.8 KiB
JavaScript
Executable File
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
|