wed
Version:
Wed is a schema-aware editor for XML documents.
141 lines (138 loc) • 4.59 kB
JavaScript
define(function(require,exports,module){
import { subscribeToResult } from '../util/subscribeToResult';
import { OuterSubscriber } from '../OuterSubscriber';
import { map } from './map';
import { from } from '../observable/from';
/* 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>
*
* <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): 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 `resultSelector`) to each item emitted
* by the source Observable and merging the results of the Observables obtained
* from this transformation.
* @method mergeMap
* @owner Observable
*/
export function mergeMap(project, resultSelector, concurrent = Number.POSITIVE_INFINITY) {
if (typeof resultSelector === 'function') {
// DEPRECATED PATH
return (source) => source.pipe(mergeMap((a, i) => from(project(a, i)).pipe(map((b, ii) => resultSelector(a, b, i, ii))), concurrent));
}
else if (typeof resultSelector === 'number') {
concurrent = resultSelector;
}
return (source) => source.lift(new MergeMapOperator(project, concurrent));
}
export class MergeMapOperator {
constructor(project, concurrent = Number.POSITIVE_INFINITY) {
this.project = project;
this.concurrent = concurrent;
}
call(observer, source) {
return source.subscribe(new MergeMapSubscriber(observer, this.project, this.concurrent));
}
}
/**
* We need this JSDoc comment for affecting ESDoc.
* @ignore
* @extends {Ignored}
*/
export class MergeMapSubscriber extends OuterSubscriber {
constructor(destination, project, concurrent = Number.POSITIVE_INFINITY) {
super(destination);
this.project = project;
this.concurrent = concurrent;
this.hasCompleted = false;
this.buffer = [];
this.active = 0;
this.index = 0;
}
_next(value) {
if (this.active < this.concurrent) {
this._tryNext(value);
}
else {
this.buffer.push(value);
}
}
_tryNext(value) {
let result;
const index = this.index++;
try {
result = this.project(value, index);
}
catch (err) {
this.destination.error(err);
return;
}
this.active++;
this._innerSub(result, value, index);
}
_innerSub(ish, value, index) {
this.add(subscribeToResult(this, ish, value, index));
}
_complete() {
this.hasCompleted = true;
if (this.active === 0 && this.buffer.length === 0) {
this.destination.complete();
}
}
notifyNext(outerValue, innerValue, outerIndex, innerIndex, innerSub) {
this.destination.next(innerValue);
}
notifyComplete(innerSub) {
const 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();
}
}
}
//# sourceMappingURL=mergeMap.js.map
return module.exports;
});