mergeMap.js
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"use strict";
var __extends = (this && this.__extends) || function (d, b) {
for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
function __() { this.constructor = d; }
d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
};
var subscribeToResult_1 = require('../util/subscribeToResult');
var OuterSubscriber_1 = require('../OuterSubscriber');
/* tslint:disable: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>
*
* <img src="./img/mergeMap.png" width="100%">
*
* 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 <caption>Map and flatten each letter to an Observable ticking every 1 second</caption>
* var letters = Rx.Observable.of('a', 'b', 'c');
* var result = letters.mergeMap(x =>
* Rx.Observable.interval(1000).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): Observable} project A function
* that, when applied to an item emitted by the source Observable, returns an
* Observable.
* @param {function(outerValue: T, innerValue: I, outerIndex: number, innerIndex: number): any} [resultSelector]
* A function to produce the value on the output Observable based on the values
* and the indices of the source (outer) emission and the inner Observable
* emission. The arguments passed to this function are:
* - `outerValue`: the value that came from the source
* - `innerValue`: the value that came from the projected Observable
* - `outerIndex`: the "index" of the value that came from the source
* - `innerIndex`: the "index" of the value from the projected 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 `resultSelector`) to each item emitted
* by the source Observable and merging the results of the Observables obtained
* from this transformation.
* @method mergeMap
* @owner Observable
*/
function mergeMap(project, resultSelector, concurrent) {
if (concurrent === void 0) { concurrent = Number.POSITIVE_INFINITY; }
if (typeof resultSelector === 'number') {
concurrent = resultSelector;
resultSelector = null;
}
return this.lift(new MergeMapOperator(project, resultSelector, concurrent));
}
exports.mergeMap = mergeMap;
var MergeMapOperator = (function () {
function MergeMapOperator(project, resultSelector, concurrent) {
if (concurrent === void 0) { concurrent = Number.POSITIVE_INFINITY; }
this.project = project;
this.resultSelector = resultSelector;
this.concurrent = concurrent;
}
MergeMapOperator.prototype.call = function (observer, source) {
return source.subscribe(new MergeMapSubscriber(observer, this.project, this.resultSelector, this.concurrent));
};
return MergeMapOperator;
}());
exports.MergeMapOperator = MergeMapOperator;
/**
* We need this JSDoc comment for affecting ESDoc.
* @ignore
* @extends {Ignored}
*/
var MergeMapSubscriber = (function (_super) {
__extends(MergeMapSubscriber, _super);
function MergeMapSubscriber(destination, project, resultSelector, concurrent) {
if (concurrent === void 0) { concurrent = Number.POSITIVE_INFINITY; }
_super.call(this, destination);
this.project = project;
this.resultSelector = resultSelector;
this.concurrent = concurrent;
this.hasCompleted = false;
this.buffer = [];
this.active = 0;
this.index = 0;
}
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, value, index);
};
MergeMapSubscriber.prototype._innerSub = function (ish, value, index) {
this.add(subscribeToResult_1.subscribeToResult(this, ish, value, index));
};
MergeMapSubscriber.prototype._complete = function () {
this.hasCompleted = true;
if (this.active === 0 && this.buffer.length === 0) {
this.destination.complete();
}
};
MergeMapSubscriber.prototype.notifyNext = function (outerValue, innerValue, outerIndex, innerIndex, innerSub) {
if (this.resultSelector) {
this._notifyResultSelector(outerValue, innerValue, outerIndex, innerIndex);
}
else {
this.destination.next(innerValue);
}
};
MergeMapSubscriber.prototype._notifyResultSelector = function (outerValue, innerValue, outerIndex, innerIndex) {
var result;
try {
result = this.resultSelector(outerValue, innerValue, outerIndex, innerIndex);
}
catch (err) {
this.destination.error(err);
return;
}
this.destination.next(result);
};
MergeMapSubscriber.prototype.notifyComplete = function (innerSub) {
var buffer = this.buffer;
this.remove(innerSub);
this.active--;
if (buffer.length > 0) {
this._next(buffer.shift());
}
else if (this.active === 0 && this.hasCompleted) {
this.destination.complete();
}
};
return MergeMapSubscriber;
}(OuterSubscriber_1.OuterSubscriber));
exports.MergeMapSubscriber = MergeMapSubscriber;
//# sourceMappingURL=mergeMap.js.map