Observable.js
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"use strict";
var root_1 = require('./util/root');
var toSubscriber_1 = require('./util/toSubscriber');
var observable_1 = require('./symbol/observable');
/**
* A representation of any set of values over any amount of time. This the most basic building block
* of RxJS.
*
* @class Observable<T>
*/
var Observable = (function () {
/**
* @constructor
* @param {Function} subscribe the function that is called when the Observable is
* initially subscribed to. This function is given a Subscriber, to which new values
* can be `next`ed, or an `error` method can be called to raise an error, or
* `complete` can be called to notify of a successful completion.
*/
function Observable(subscribe) {
this._isScalar = false;
if (subscribe) {
this._subscribe = subscribe;
}
}
/**
* Creates a new Observable, with this Observable as the source, and the passed
* operator defined as the new observable's operator.
* @method lift
* @param {Operator} operator the operator defining the operation to take on the observable
* @return {Observable} a new observable with the Operator applied
*/
Observable.prototype.lift = function (operator) {
var observable = new Observable();
observable.source = this;
observable.operator = operator;
return observable;
};
Observable.prototype.subscribe = function (observerOrNext, error, complete) {
var operator = this.operator;
var sink = toSubscriber_1.toSubscriber(observerOrNext, error, complete);
if (operator) {
operator.call(sink, this.source);
}
else {
sink.add(this._subscribe(sink));
}
if (sink.syncErrorThrowable) {
sink.syncErrorThrowable = false;
if (sink.syncErrorThrown) {
throw sink.syncErrorValue;
}
}
return sink;
};
/**
* @method forEach
* @param {Function} next a handler for each value emitted by the observable
* @param {PromiseConstructor} [PromiseCtor] a constructor function used to instantiate the Promise
* @return {Promise} a promise that either resolves on observable completion or
* rejects with the handled error
*/
Observable.prototype.forEach = function (next, PromiseCtor) {
var _this = this;
if (!PromiseCtor) {
if (root_1.root.Rx && root_1.root.Rx.config && root_1.root.Rx.config.Promise) {
PromiseCtor = root_1.root.Rx.config.Promise;
}
else if (root_1.root.Promise) {
PromiseCtor = root_1.root.Promise;
}
}
if (!PromiseCtor) {
throw new Error('no Promise impl found');
}
return new PromiseCtor(function (resolve, reject) {
var subscription = _this.subscribe(function (value) {
if (subscription) {
// if there is a subscription, then we can surmise
// the next handling is asynchronous. Any errors thrown
// need to be rejected explicitly and unsubscribe must be
// called manually
try {
next(value);
}
catch (err) {
reject(err);
subscription.unsubscribe();
}
}
else {
// if there is NO subscription, then we're getting a nexted
// value synchronously during subscription. We can just call it.
// If it errors, Observable's `subscribe` will ensure the
// unsubscription logic is called, then synchronously rethrow the error.
// After that, Promise will trap the error and send it
// down the rejection path.
next(value);
}
}, reject, resolve);
});
};
Observable.prototype._subscribe = function (subscriber) {
return this.source.subscribe(subscriber);
};
/**
* An interop point defined by the es7-observable spec https://github.com/zenparsing/es-observable
* @method Symbol.observable
* @return {Observable} this instance of the observable
*/
Observable.prototype[observable_1.$$observable] = function () {
return this;
};
// HACK: Since TypeScript inherits static properties too, we have to
// fight against TypeScript here so Subject can have a different static create signature
/**
* Creates a new cold Observable by calling the Observable constructor
* @static true
* @owner Observable
* @method create
* @param {Function} subscribe? the subscriber function to be passed to the Observable constructor
* @return {Observable} a new cold observable
*/
Observable.create = function (subscribe) {
return new Observable(subscribe);
};
return Observable;
}());
exports.Observable = Observable;
//# sourceMappingURL=Observable.js.map