@reactivex/rxjs
Version:
Reactive Extensions for modern JavaScript
155 lines • 5.78 kB
JavaScript
"use strict";
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 innerSubscribe_1 = require("../innerSubscribe");
/**
* Applies an accumulator function over the source Observable where the
* accumulator function itself returns an Observable, then each intermediate
* Observable returned is merged into the output Observable.
*
* <span class="informal">It's like {@link scan}, but the Observables returned
* by the accumulator are merged into the outer Observable.</span>
*
* ## Example
* Count the number of click events
* ```ts
* import { fromEvent, of } from 'rxjs';
* import { mapTo, mergeScan } from 'rxjs/operators';
*
* const click$ = fromEvent(document, 'click');
* const one$ = click$.pipe(mapTo(1));
* const seed = 0;
* const count$ = one$.pipe(
* mergeScan((acc, one) => of(acc + one), seed),
* );
* count$.subscribe(x => console.log(x));
*
* // Results:
* // 1
* // 2
* // 3
* // 4
* // ...and so on for each click
* ```
*
* @param {function(acc: R, value: T): Observable<R>} accumulator
* The accumulator function called on each source value.
* @param seed The initial accumulation value.
* @param {number} [concurrent=Number.POSITIVE_INFINITY] Maximum number of
* input Observables being subscribed to concurrently.
* @return {Observable<R>} An observable of the accumulated values.
* @method mergeScan
* @owner Observable
*/
function mergeScan(accumulator, seed, concurrent) {
if (concurrent === void 0) { concurrent = Number.POSITIVE_INFINITY; }
return function (source) { return source.lift(new MergeScanOperator(accumulator, seed, concurrent)); };
}
exports.mergeScan = mergeScan;
var MergeScanOperator = /** @class */ (function () {
function MergeScanOperator(accumulator, seed, concurrent) {
this.accumulator = accumulator;
this.seed = seed;
this.concurrent = concurrent;
}
MergeScanOperator.prototype.call = function (subscriber, source) {
return source.subscribe(new MergeScanSubscriber(subscriber, this.accumulator, this.seed, this.concurrent));
};
return MergeScanOperator;
}());
exports.MergeScanOperator = MergeScanOperator;
/**
* We need this JSDoc comment for affecting ESDoc.
* @ignore
* @extends {Ignored}
*/
var MergeScanSubscriber = /** @class */ (function (_super) {
__extends(MergeScanSubscriber, _super);
function MergeScanSubscriber(destination, accumulator, acc, concurrent) {
var _this = _super.call(this, destination) || this;
_this.accumulator = accumulator;
_this.acc = acc;
_this.concurrent = concurrent;
_this.hasValue = false;
_this.hasCompleted = false;
_this.buffer = [];
_this.active = 0;
_this.index = 0;
return _this;
}
MergeScanSubscriber.prototype._next = function (value) {
if (this.active < this.concurrent) {
var index = this.index++;
var destination = this.destination;
var ish = void 0;
try {
var accumulator = this.accumulator;
ish = accumulator(this.acc, value, index);
}
catch (e) {
return destination.error(e);
}
this.active++;
this._innerSub(ish);
}
else {
this.buffer.push(value);
}
};
MergeScanSubscriber.prototype._innerSub = function (ish) {
var innerSubscriber = new innerSubscribe_1.SimpleInnerSubscriber(this);
var destination = this.destination;
destination.add(innerSubscriber);
var innerSubscription = innerSubscribe_1.innerSubscribe(ish, 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);
}
};
MergeScanSubscriber.prototype._complete = function () {
this.hasCompleted = true;
if (this.active === 0 && this.buffer.length === 0) {
if (this.hasValue === false) {
this.destination.next(this.acc);
}
this.destination.complete();
}
this.unsubscribe();
};
MergeScanSubscriber.prototype.notifyNext = function (innerValue) {
var destination = this.destination;
this.acc = innerValue;
this.hasValue = true;
destination.next(innerValue);
};
MergeScanSubscriber.prototype.notifyComplete = function () {
var buffer = this.buffer;
this.active--;
if (buffer.length > 0) {
this._next(buffer.shift());
}
else if (this.active === 0 && this.hasCompleted) {
if (this.hasValue === false) {
this.destination.next(this.acc);
}
this.destination.complete();
}
};
return MergeScanSubscriber;
}(innerSubscribe_1.SimpleOuterSubscriber));
exports.MergeScanSubscriber = MergeScanSubscriber;
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