@reactivex/rxjs
Version:
Reactive Extensions for modern JavaScript
176 lines • 6.58 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.
*
* <span class="informal">Maps each value to an Observable, then flattens all of
* these inner Observables using {@link mergeAll}.</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 Observable, and then merging those resulting Observables and
* emitting the results of this merger.
*
* ## Example
* Map and flatten each letter to an Observable ticking every 1 second
* ```ts
* import { of, interval } from 'rxjs';
* import { mergeMap, map } from 'rxjs/operators';
*
* const letters = of('a', 'b', 'c');
* const result = letters.pipe(
* mergeMap(x => interval(1000).pipe(map(i => x+i))),
* );
* result.subscribe(x => console.log(x));
*
* // Results in the following:
* // a0
* // b0
* // c0
* // a1
* // b1
* // c1
* // continues to list a,b,c with respective ascending integers
* ```
*
* @see {@link concatMap}
* @see {@link exhaustMap}
* @see {@link merge}
* @see {@link mergeAll}
* @see {@link mergeMapTo}
* @see {@link mergeScan}
* @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.
* @param {number} [concurrent=Number.POSITIVE_INFINITY] Maximum number of input
* Observables being subscribed to concurrently.
* @return {Observable} An Observable that emits the result of applying the
* projection function (and the optional deprecated `resultSelector`) to each item
* emitted by the source Observable and merging the results of the Observables
* obtained from this transformation.
*/
function mergeMap(project, resultSelector, concurrent) {
if (concurrent === void 0) { concurrent = Number.POSITIVE_INFINITY; }
if (typeof resultSelector === 'function') {
// DEPRECATED PATH
return function (source) { return source.pipe(mergeMap(function (a, i) { return from_1.from(project(a, i)).pipe(map_1.map(function (b, ii) { return resultSelector(a, b, i, ii); })); }, concurrent)); };
}
else if (typeof resultSelector === 'number') {
concurrent = resultSelector;
}
return function (source) { return source.lift(new MergeMapOperator(project, concurrent)); };
}
exports.mergeMap = mergeMap;
var MergeMapOperator = /** @class */ (function () {
function MergeMapOperator(project, concurrent) {
if (concurrent === void 0) { concurrent = Number.POSITIVE_INFINITY; }
this.project = project;
this.concurrent = concurrent;
}
MergeMapOperator.prototype.call = function (observer, source) {
return source.subscribe(new MergeMapSubscriber(observer, this.project, this.concurrent));
};
return MergeMapOperator;
}());
exports.MergeMapOperator = MergeMapOperator;
/**
* We need this JSDoc comment for affecting ESDoc.
* @ignore
* @extends {Ignored}
*/
var MergeMapSubscriber = /** @class */ (function (_super) {
__extends(MergeMapSubscriber, _super);
function MergeMapSubscriber(destination, project, concurrent) {
if (concurrent === void 0) { concurrent = Number.POSITIVE_INFINITY; }
var _this = _super.call(this, destination) || this;
_this.project = project;
_this.concurrent = concurrent;
_this.hasCompleted = false;
_this.buffer = [];
_this.active = 0;
_this.index = 0;
return _this;
}
MergeMapSubscriber.prototype._next = function (value) {
if (this.active < this.concurrent) {
this._tryNext(value);
}
else {
this.buffer.push(value);
}
};
MergeMapSubscriber.prototype._tryNext = function (value) {
var result;
var index = this.index++;
try {
result = this.project(value, index);
}
catch (err) {
this.destination.error(err);
return;
}
this.active++;
this._innerSub(result);
};
MergeMapSubscriber.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);
}
};
MergeMapSubscriber.prototype._complete = function () {
this.hasCompleted = true;
if (this.active === 0 && this.buffer.length === 0) {
this.destination.complete();
}
this.unsubscribe();
};
MergeMapSubscriber.prototype.notifyNext = function (innerValue) {
this.destination.next(innerValue);
};
MergeMapSubscriber.prototype.notifyComplete = function () {
var buffer = this.buffer;
this.active--;
if (buffer.length > 0) {
this._next(buffer.shift());
}
else if (this.active === 0 && this.hasCompleted) {
this.destination.complete();
}
};
return MergeMapSubscriber;
}(innerSubscribe_1.SimpleOuterSubscriber));
exports.MergeMapSubscriber = MergeMapSubscriber;
/**
* @deprecated renamed. Use {@link mergeMap}
*/
exports.flatMap = mergeMap;
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