99 lines
3.6 KiB
JavaScript
99 lines
3.6 KiB
JavaScript
|
import { isFunction } from '../util/isFunction';
|
||
|
|
import { Observable } from '../Observable';
|
||
|
|
import { Subscription } from '../Subscription';
|
||
|
|
/**
|
||
|
|
* We need this JSDoc comment for affecting ESDoc.
|
||
|
|
* @extends {Ignored}
|
||
|
|
* @hide true
|
||
|
|
*/
|
||
|
|
export class FromEventPatternObservable extends Observable {
|
||
|
|
constructor(addHandler, removeHandler, selector) {
|
||
|
|
super();
|
||
|
|
this.addHandler = addHandler;
|
||
|
|
this.removeHandler = removeHandler;
|
||
|
|
this.selector = selector;
|
||
|
|
}
|
||
|
|
/**
|
||
|
|
* Creates an Observable from an API based on addHandler/removeHandler
|
||
|
|
* functions.
|
||
|
|
*
|
||
|
|
* <span class="informal">Converts any addHandler/removeHandler API to an
|
||
|
|
* Observable.</span>
|
||
|
|
*
|
||
|
|
* <img src="./img/fromEventPattern.png" width="100%">
|
||
|
|
*
|
||
|
|
* Creates an Observable by using the `addHandler` and `removeHandler`
|
||
|
|
* functions to add and remove the handlers, with an optional selector
|
||
|
|
* function to project the event arguments to a result. The `addHandler` is
|
||
|
|
* called when the output Observable is subscribed, and `removeHandler` is
|
||
|
|
* called when the Subscription is unsubscribed.
|
||
|
|
*
|
||
|
|
* @example <caption>Emits clicks happening on the DOM document</caption>
|
||
|
|
* function addClickHandler(handler) {
|
||
|
|
* document.addEventListener('click', handler);
|
||
|
|
* }
|
||
|
|
*
|
||
|
|
* function removeClickHandler(handler) {
|
||
|
|
* document.removeEventListener('click', handler);
|
||
|
|
* }
|
||
|
|
*
|
||
|
|
* var clicks = Rx.Observable.fromEventPattern(
|
||
|
|
* addClickHandler,
|
||
|
|
* removeClickHandler
|
||
|
|
* );
|
||
|
|
* clicks.subscribe(x => console.log(x));
|
||
|
|
*
|
||
|
|
* @see {@link from}
|
||
|
|
* @see {@link fromEvent}
|
||
|
|
*
|
||
|
|
* @param {function(handler: Function): any} addHandler A function that takes
|
||
|
|
* a `handler` function as argument and attaches it somehow to the actual
|
||
|
|
* source of events.
|
||
|
|
* @param {function(handler: Function, signal?: any): void} [removeHandler] An optional function that
|
||
|
|
* takes a `handler` function as argument and removes it in case it was
|
||
|
|
* previously attached using `addHandler`. if addHandler returns signal to teardown when remove,
|
||
|
|
* removeHandler function will forward it.
|
||
|
|
* @param {function(...args: any): T} [selector] An optional function to
|
||
|
|
* post-process results. It takes the arguments from the event handler and
|
||
|
|
* should return a single value.
|
||
|
|
* @return {Observable<T>}
|
||
|
|
* @static true
|
||
|
|
* @name fromEventPattern
|
||
|
|
* @owner Observable
|
||
|
|
*/
|
||
|
|
static create(addHandler, removeHandler, selector) {
|
||
|
|
return new FromEventPatternObservable(addHandler, removeHandler, selector);
|
||
|
|
}
|
||
|
|
/** @deprecated internal use only */ _subscribe(subscriber) {
|
||
|
|
const removeHandler = this.removeHandler;
|
||
|
|
const handler = !!this.selector ? (...args) => {
|
||
|
|
this._callSelector(subscriber, args);
|
||
|
|
} : function (e) { subscriber.next(e); };
|
||
|
|
const retValue = this._callAddHandler(handler, subscriber);
|
||
|
|
if (!isFunction(removeHandler)) {
|
||
|
|
return;
|
||
|
|
}
|
||
|
|
subscriber.add(new Subscription(() => {
|
||
|
|
//TODO: determine whether or not to forward to error handler
|
||
|
|
removeHandler(handler, retValue);
|
||
|
|
}));
|
||
|
|
}
|
||
|
|
_callSelector(subscriber, args) {
|
||
|
|
try {
|
||
|
|
const result = this.selector(...args);
|
||
|
|
subscriber.next(result);
|
||
|
|
}
|
||
|
|
catch (e) {
|
||
|
|
subscriber.error(e);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
_callAddHandler(handler, errorSubscriber) {
|
||
|
|
try {
|
||
|
|
return this.addHandler(handler) || null;
|
||
|
|
}
|
||
|
|
catch (e) {
|
||
|
|
errorSubscriber.error(e);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
//# sourceMappingURL=FromEventPatternObservable.js.map
|