@reactivex/rxjs
Version:
Reactive Extensions for modern JavaScript
143 lines • 5.34 kB
JavaScript
;
var __extends = (this && this.__extends) || (function () {
var extendStatics = function (d, b) {
extendStatics = Object.setPrototypeOf ||
({ __proto__: [] } instanceof Array && function (d, b) { d.__proto__ = b; }) ||
function (d, b) { for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p]; };
return extendStatics(d, b);
}
return function (d, b) {
extendStatics(d, b);
function __() { this.constructor = d; }
d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
};
})();
Object.defineProperty(exports, "__esModule", { value: true });
var Subscriber_1 = require("../Subscriber");
var noop_1 = require("../util/noop");
var isFunction_1 = require("../util/isFunction");
/* 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>
*
* 
*
* 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 `tap` is not subscribed, the side effects specified by the
* Observer will never happen. `tap` therefore simply spies on existing
* execution, it does not trigger an execution to happen like `subscribe` does.
*
* ## Example
* Map every click to the clientX position of that click, while also logging the click event
* ```ts
* import { fromEvent } from 'rxjs';
* import { tap, map } from 'rxjs/operators';
*
* const clicks = fromEvent(document, 'click');
* const positions = clicks.pipe(
* tap(ev => console.log(ev)),
* map(ev => ev.clientX),
* );
* positions.subscribe(x => console.log(x));
* ```
*
* @see {@link map}
* @see {@link Observable#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
*/
function tap(nextOrObserver, error, complete) {
return function tapOperatorFunction(source) {
return source.lift(new DoOperator(nextOrObserver, error, complete));
};
}
exports.tap = tap;
var DoOperator = /** @class */ (function () {
function DoOperator(nextOrObserver, error, complete) {
this.nextOrObserver = nextOrObserver;
this.error = error;
this.complete = complete;
}
DoOperator.prototype.call = function (subscriber, source) {
return source.subscribe(new TapSubscriber(subscriber, this.nextOrObserver, this.error, this.complete));
};
return DoOperator;
}());
/**
* We need this JSDoc comment for affecting ESDoc.
* @ignore
* @extends {Ignored}
*/
var TapSubscriber = /** @class */ (function (_super) {
__extends(TapSubscriber, _super);
function TapSubscriber(destination, observerOrNext, error, complete) {
var _this = _super.call(this, destination) || this;
_this._tapNext = noop_1.noop;
_this._tapError = noop_1.noop;
_this._tapComplete = noop_1.noop;
_this._tapError = error || noop_1.noop;
_this._tapComplete = complete || noop_1.noop;
if (isFunction_1.isFunction(observerOrNext)) {
_this._context = _this;
_this._tapNext = observerOrNext;
}
else if (observerOrNext) {
_this._context = observerOrNext;
_this._tapNext = observerOrNext.next || noop_1.noop;
_this._tapError = observerOrNext.error || noop_1.noop;
_this._tapComplete = observerOrNext.complete || noop_1.noop;
}
return _this;
}
TapSubscriber.prototype._next = function (value) {
try {
this._tapNext.call(this._context, value);
}
catch (err) {
this.destination.error(err);
return;
}
this.destination.next(value);
};
TapSubscriber.prototype._error = function (err) {
try {
this._tapError.call(this._context, err);
}
catch (err) {
this.destination.error(err);
return;
}
this.destination.error(err);
};
TapSubscriber.prototype._complete = function () {
try {
this._tapComplete.call(this._context);
}
catch (err) {
this.destination.error(err);
return;
}
return this.destination.complete();
};
return TapSubscriber;
}(Subscriber_1.Subscriber));
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