// Copyright 2011 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
/**
* @fileoverview EventTracker is a simple class that manages the addition and
* removal of DOM event listeners. In particular, it keeps track of all
* listeners that have been added and makes it easy to remove some or all of
* them without requiring all the information again. This is particularly handy
* when the listener is a generated function such as a lambda or the result of
* calling Function.bind.
*/
cr.define('cr', function() {
/* #export */ class EventTracker {
/**
* Create an EventTracker to track a set of events.
* EventTracker instances are typically tied 1:1 with other objects or
* DOM elements whose listeners should be removed when the object is
* disposed or the corresponding elements are removed from the DOM.
*/
constructor() {
/**
* @type {Array<EventTrackerEntry>}
* @private
*/
this.listeners_ = [];
}
/**
* Add an event listener - replacement for EventTarget.addEventListener.
* @param {!EventTarget} target The DOM target to add a listener to.
* @param {string} eventType The type of event to subscribe to.
* @param {EventListener|Function} listener The listener to add.
* @param {boolean=} capture Whether to invoke during the capture phase.
*/
add(target, eventType, listener, capture = false) {
const h = {
target: target,
eventType: eventType,
listener: listener,
capture: capture,
};
this.listeners_.push(h);
target.addEventListener(eventType, listener, capture);
}
/**
* Remove any specified event listeners added with this EventTracker.
* @param {!EventTarget} target The DOM target to remove a listener from.
* @param {?string} eventType The type of event to remove.
*/
remove(target, eventType) {
this.listeners_ = this.listeners_.filter(listener => {
if (listener.target === target &&
(!eventType || (listener.eventType === eventType))) {
EventTracker.removeEventListener(listener);
return false;
}
return true;
});
}
/** Remove all event listeners added with this EventTracker. */
removeAll() {
this.listeners_.forEach(
listener => EventTracker.removeEventListener(listener));
this.listeners_ = [];
}
/**
* Remove a single event listener given it's tracking entry. It's up to the
* caller to ensure the entry is removed from listeners_.
* @param {EventTrackerEntry} entry The entry describing the listener to
* remove.
*/
static removeEventListener(entry) {
entry.target.removeEventListener(
entry.eventType, entry.listener, entry.capture);
}
}
/**
* The type of the internal tracking entry.
* @typedef {{target: !EventTarget,
* eventType: string,
* listener: (EventListener|Function),
* capture: boolean}}
*/
let EventTrackerEntry;
// #cr_define_end
console.warn('crbug/1173575, non-JS module files deprecated.');
return {EventTracker};
});
Codebase Browser
chromium