99 lines
3.9 KiB
JavaScript
Executable File
99 lines
3.9 KiB
JavaScript
Executable File
"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 Observable_1 = require('../Observable');
|
|
var subscribeToResult_1 = require('../util/subscribeToResult');
|
|
var OuterSubscriber_1 = require('../OuterSubscriber');
|
|
/**
|
|
* We need this JSDoc comment for affecting ESDoc.
|
|
* @extends {Ignored}
|
|
* @hide true
|
|
*/
|
|
var DeferObservable = (function (_super) {
|
|
__extends(DeferObservable, _super);
|
|
function DeferObservable(observableFactory) {
|
|
_super.call(this);
|
|
this.observableFactory = observableFactory;
|
|
}
|
|
/**
|
|
* Creates an Observable that, on subscribe, calls an Observable factory to
|
|
* make an Observable for each new Observer.
|
|
*
|
|
* <span class="informal">Creates the Observable lazily, that is, only when it
|
|
* is subscribed.
|
|
* </span>
|
|
*
|
|
* <img src="./img/defer.png" width="100%">
|
|
*
|
|
* `defer` allows you to create the Observable only when the Observer
|
|
* subscribes, and create a fresh Observable for each Observer. It waits until
|
|
* an Observer subscribes to it, and then it generates an Observable,
|
|
* typically with an Observable factory function. It does this afresh for each
|
|
* subscriber, so although each subscriber may think it is subscribing to the
|
|
* same Observable, in fact each subscriber gets its own individual
|
|
* Observable.
|
|
*
|
|
* @example <caption>Subscribe to either an Observable of clicks or an Observable of interval, at random</caption>
|
|
* var clicksOrInterval = Rx.Observable.defer(function () {
|
|
* if (Math.random() > 0.5) {
|
|
* return Rx.Observable.fromEvent(document, 'click');
|
|
* } else {
|
|
* return Rx.Observable.interval(1000);
|
|
* }
|
|
* });
|
|
* clicksOrInterval.subscribe(x => console.log(x));
|
|
*
|
|
* // Results in the following behavior:
|
|
* // If the result of Math.random() is greater than 0.5 it will listen
|
|
* // for clicks anywhere on the "document"; when document is clicked it
|
|
* // will log a MouseEvent object to the console. If the result is less
|
|
* // than 0.5 it will emit ascending numbers, one every second(1000ms).
|
|
*
|
|
* @see {@link create}
|
|
*
|
|
* @param {function(): SubscribableOrPromise} observableFactory The Observable
|
|
* factory function to invoke for each Observer that subscribes to the output
|
|
* Observable. May also return a Promise, which will be converted on the fly
|
|
* to an Observable.
|
|
* @return {Observable} An Observable whose Observers' subscriptions trigger
|
|
* an invocation of the given Observable factory function.
|
|
* @static true
|
|
* @name defer
|
|
* @owner Observable
|
|
*/
|
|
DeferObservable.create = function (observableFactory) {
|
|
return new DeferObservable(observableFactory);
|
|
};
|
|
/** @deprecated internal use only */ DeferObservable.prototype._subscribe = function (subscriber) {
|
|
return new DeferSubscriber(subscriber, this.observableFactory);
|
|
};
|
|
return DeferObservable;
|
|
}(Observable_1.Observable));
|
|
exports.DeferObservable = DeferObservable;
|
|
var DeferSubscriber = (function (_super) {
|
|
__extends(DeferSubscriber, _super);
|
|
function DeferSubscriber(destination, factory) {
|
|
_super.call(this, destination);
|
|
this.factory = factory;
|
|
this.tryDefer();
|
|
}
|
|
DeferSubscriber.prototype.tryDefer = function () {
|
|
try {
|
|
this._callFactory();
|
|
}
|
|
catch (err) {
|
|
this._error(err);
|
|
}
|
|
};
|
|
DeferSubscriber.prototype._callFactory = function () {
|
|
var result = this.factory();
|
|
if (result) {
|
|
this.add(subscribeToResult_1.subscribeToResult(this, result));
|
|
}
|
|
};
|
|
return DeferSubscriber;
|
|
}(OuterSubscriber_1.OuterSubscriber));
|
|
//# sourceMappingURL=DeferObservable.js.map
|