work.suroh.tk/node_modules/rxjs/_esm2015/observable/FromEventObservable.js

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2019-12-02 12:22:45 +00:00
import { Observable } from '../Observable';
import { tryCatch } from '../util/tryCatch';
import { isFunction } from '../util/isFunction';
import { errorObject } from '../util/errorObject';
import { Subscription } from '../Subscription';
const toString = Object.prototype.toString;
function isNodeStyleEventEmitter(sourceObj) {
return !!sourceObj && typeof sourceObj.addListener === 'function' && typeof sourceObj.removeListener === 'function';
}
function isJQueryStyleEventEmitter(sourceObj) {
return !!sourceObj && typeof sourceObj.on === 'function' && typeof sourceObj.off === 'function';
}
function isNodeList(sourceObj) {
return !!sourceObj && toString.call(sourceObj) === '[object NodeList]';
}
function isHTMLCollection(sourceObj) {
return !!sourceObj && toString.call(sourceObj) === '[object HTMLCollection]';
}
function isEventTarget(sourceObj) {
return !!sourceObj && typeof sourceObj.addEventListener === 'function' && typeof sourceObj.removeEventListener === 'function';
}
/**
* We need this JSDoc comment for affecting ESDoc.
* @extends {Ignored}
* @hide true
*/
export class FromEventObservable extends Observable {
constructor(sourceObj, eventName, selector, options) {
super();
this.sourceObj = sourceObj;
this.eventName = eventName;
this.selector = selector;
this.options = options;
}
/* tslint:enable:max-line-length */
/**
* Creates an Observable that emits events of a specific type coming from the
* given event target.
*
* <span class="informal">Creates an Observable from DOM events, or Node.js
* EventEmitter events or others.</span>
*
* <img src="./img/fromEvent.png" width="100%">
*
* `fromEvent` accepts as a first argument event target, which is an object with methods
* for registering event handler functions. As a second argument it takes string that indicates
* type of event we want to listen for. `fromEvent` supports selected types of event targets,
* which are described in detail below. If your event target does not match any of the ones listed,
* you should use {@link fromEventPattern}, which can be used on arbitrary APIs.
* When it comes to APIs supported by `fromEvent`, their methods for adding and removing event
* handler functions have different names, but they all accept a string describing event type
* and function itself, which will be called whenever said event happens.
*
* Every time resulting Observable is subscribed, event handler function will be registered
* to event target on given event type. When that event fires, value
* passed as a first argument to registered function will be emitted by output Observable.
* When Observable is unsubscribed, function will be unregistered from event target.
*
* Note that if event target calls registered function with more than one argument, second
* and following arguments will not appear in resulting stream. In order to get access to them,
* you can pass to `fromEvent` optional project function, which will be called with all arguments
* passed to event handler. Output Observable will then emit value returned by project function,
* instead of the usual value.
*
* Remember that event targets listed below are checked via duck typing. It means that
* no matter what kind of object you have and no matter what environment you work in,
* you can safely use `fromEvent` on that object if it exposes described methods (provided
* of course they behave as was described above). So for example if Node.js library exposes
* event target which has the same method names as DOM EventTarget, `fromEvent` is still
* a good choice.
*
* If the API you use is more callback then event handler oriented (subscribed
* callback function fires only once and thus there is no need to manually
* unregister it), you should use {@link bindCallback} or {@link bindNodeCallback}
* instead.
*
* `fromEvent` supports following types of event targets:
*
* **DOM EventTarget**
*
* This is an object with `addEventListener` and `removeEventListener` methods.
*
* In the browser, `addEventListener` accepts - apart from event type string and event
* handler function arguments - optional third parameter, which is either an object or boolean,
* both used for additional configuration how and when passed function will be called. When
* `fromEvent` is used with event target of that type, you can provide this values
* as third parameter as well.
*
* **Node.js EventEmitter**
*
* An object with `addListener` and `removeListener` methods.
*
* **JQuery-style event target**
*
* An object with `on` and `off` methods
*
* **DOM NodeList**
*
* List of DOM Nodes, returned for example by `document.querySelectorAll` or `Node.childNodes`.
*
* Although this collection is not event target in itself, `fromEvent` will iterate over all Nodes
* it contains and install event handler function in every of them. When returned Observable
* is unsubscribed, function will be removed from all Nodes.
*
* **DOM HtmlCollection**
*
* Just as in case of NodeList it is a collection of DOM nodes. Here as well event handler function is
* installed and removed in each of elements.
*
*
* @example <caption>Emits clicks happening on the DOM document</caption>
* var clicks = Rx.Observable.fromEvent(document, 'click');
* clicks.subscribe(x => console.log(x));
*
* // Results in:
* // MouseEvent object logged to console every time a click
* // occurs on the document.
*
*
* @example <caption>Use addEventListener with capture option</caption>
* var clicksInDocument = Rx.Observable.fromEvent(document, 'click', true); // note optional configuration parameter
* // which will be passed to addEventListener
* var clicksInDiv = Rx.Observable.fromEvent(someDivInDocument, 'click');
*
* clicksInDocument.subscribe(() => console.log('document'));
* clicksInDiv.subscribe(() => console.log('div'));
*
* // By default events bubble UP in DOM tree, so normally
* // when we would click on div in document
* // "div" would be logged first and then "document".
* // Since we specified optional `capture` option, document
* // will catch event when it goes DOWN DOM tree, so console
* // will log "document" and then "div".
*
* @see {@link bindCallback}
* @see {@link bindNodeCallback}
* @see {@link fromEventPattern}
*
* @param {EventTargetLike} target The DOM EventTarget, Node.js
* EventEmitter, JQuery-like event target, NodeList or HTMLCollection to attach the event handler to.
* @param {string} eventName The event name of interest, being emitted by the
* `target`.
* @param {EventListenerOptions} [options] Options to pass through to addEventListener
* @param {SelectorMethodSignature<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 fromEvent
* @owner Observable
*/
static create(target, eventName, options, selector) {
if (isFunction(options)) {
selector = options;
options = undefined;
}
return new FromEventObservable(target, eventName, selector, options);
}
static setupSubscription(sourceObj, eventName, handler, subscriber, options) {
let unsubscribe;
if (isNodeList(sourceObj) || isHTMLCollection(sourceObj)) {
for (let i = 0, len = sourceObj.length; i < len; i++) {
FromEventObservable.setupSubscription(sourceObj[i], eventName, handler, subscriber, options);
}
}
else if (isEventTarget(sourceObj)) {
const source = sourceObj;
sourceObj.addEventListener(eventName, handler, options);
unsubscribe = () => source.removeEventListener(eventName, handler, options);
}
else if (isJQueryStyleEventEmitter(sourceObj)) {
const source = sourceObj;
sourceObj.on(eventName, handler);
unsubscribe = () => source.off(eventName, handler);
}
else if (isNodeStyleEventEmitter(sourceObj)) {
const source = sourceObj;
sourceObj.addListener(eventName, handler);
unsubscribe = () => source.removeListener(eventName, handler);
}
else {
throw new TypeError('Invalid event target');
}
subscriber.add(new Subscription(unsubscribe));
}
/** @deprecated internal use only */ _subscribe(subscriber) {
const sourceObj = this.sourceObj;
const eventName = this.eventName;
const options = this.options;
const selector = this.selector;
let handler = selector ? (...args) => {
let result = tryCatch(selector)(...args);
if (result === errorObject) {
subscriber.error(errorObject.e);
}
else {
subscriber.next(result);
}
} : (e) => subscriber.next(e);
FromEventObservable.setupSubscription(sourceObj, eventName, handler, subscriber, options);
}
}
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