@reactivex/rxjs
Version:
Reactive Extensions for modern JavaScript
150 lines • 5.85 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 map_1 = require("./map");
var from_1 = require("../observable/from");
var innerSubscribe_1 = require("../innerSubscribe");
/* tslint:enable:max-line-length */
/**
* Projects each source value to an Observable which is merged in the output
* Observable only if the previous projected Observable has completed.
*
* <span class="informal">Maps each value to an Observable, then flattens all of
* these inner Observables using {@link exhaust}.</span>
*
* 
*
* Returns an Observable that emits items based on applying a function that you
* supply to each item emitted by the source Observable, where that function
* returns an (so-called "inner") Observable. When it projects a source value to
* an Observable, the output Observable begins emitting the items emitted by
* that projected Observable. However, `exhaustMap` ignores every new projected
* Observable if the previous projected Observable has not yet completed. Once
* that one completes, it will accept and flatten the next projected Observable
* and repeat this process.
*
* ## Example
* Run a finite timer for each click, only if there is no currently active timer
* ```ts
* import { fromEvent, interval } from 'rxjs';
* import { exhaustMap, take } from 'rxjs/operators';
*
* const clicks = fromEvent(document, 'click');
* const result = clicks.pipe(
* exhaustMap(ev => interval(1000).pipe(take(5)))
* );
* result.subscribe(x => console.log(x));
* ```
*
* @see {@link concatMap}
* @see {@link exhaust}
* @see {@link mergeMap}
* @see {@link switchMap}
*
* @param {function(value: T, ?index: number): ObservableInput} project A function
* that, when applied to an item emitted by the source Observable, returns an
* Observable.
* @return {Observable} An Observable containing projected Observables
* of each item of the source, ignoring projected Observables that start before
* their preceding Observable has completed.
* @method exhaustMap
* @owner Observable
*/
function exhaustMap(project, resultSelector) {
if (resultSelector) {
// DEPRECATED PATH
return function (source) { return source.pipe(exhaustMap(function (a, i) { return from_1.from(project(a, i)).pipe(map_1.map(function (b, ii) { return resultSelector(a, b, i, ii); })); })); };
}
return function (source) {
return source.lift(new ExhaustMapOperator(project));
};
}
exports.exhaustMap = exhaustMap;
var ExhaustMapOperator = /** @class */ (function () {
function ExhaustMapOperator(project) {
this.project = project;
}
ExhaustMapOperator.prototype.call = function (subscriber, source) {
return source.subscribe(new ExhaustMapSubscriber(subscriber, this.project));
};
return ExhaustMapOperator;
}());
/**
* We need this JSDoc comment for affecting ESDoc.
* @ignore
* @extends {Ignored}
*/
var ExhaustMapSubscriber = /** @class */ (function (_super) {
__extends(ExhaustMapSubscriber, _super);
function ExhaustMapSubscriber(destination, project) {
var _this = _super.call(this, destination) || this;
_this.project = project;
_this.hasSubscription = false;
_this.hasCompleted = false;
_this.index = 0;
return _this;
}
ExhaustMapSubscriber.prototype._next = function (value) {
if (!this.hasSubscription) {
this.tryNext(value);
}
};
ExhaustMapSubscriber.prototype.tryNext = function (value) {
var result;
var index = this.index++;
try {
result = this.project(value, index);
}
catch (err) {
this.destination.error(err);
return;
}
this.hasSubscription = true;
this._innerSub(result);
};
ExhaustMapSubscriber.prototype._innerSub = function (result) {
var innerSubscriber = new innerSubscribe_1.SimpleInnerSubscriber(this);
var destination = this.destination;
destination.add(innerSubscriber);
var innerSubscription = innerSubscribe_1.innerSubscribe(result, innerSubscriber);
// The returned subscription will usually be the subscriber that was
// passed. However, interop subscribers will be wrapped and for
// unsubscriptions to chain correctly, the wrapper needs to be added, too.
if (innerSubscription !== innerSubscriber) {
destination.add(innerSubscription);
}
};
ExhaustMapSubscriber.prototype._complete = function () {
this.hasCompleted = true;
if (!this.hasSubscription) {
this.destination.complete();
}
this.unsubscribe();
};
ExhaustMapSubscriber.prototype.notifyNext = function (innerValue) {
this.destination.next(innerValue);
};
ExhaustMapSubscriber.prototype.notifyError = function (err) {
this.destination.error(err);
};
ExhaustMapSubscriber.prototype.notifyComplete = function () {
this.hasSubscription = false;
if (this.hasCompleted) {
this.destination.complete();
}
};
return ExhaustMapSubscriber;
}(innerSubscribe_1.SimpleOuterSubscriber));
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