mediocre-blog/assets/viz/2/goog/events/event.js

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2018-11-12 21:18:45 +00:00
// Copyright 2005 The Closure Library Authors. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS-IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
/**
* @fileoverview A base class for event objects.
*
*/
goog.provide('goog.events.Event');
goog.provide('goog.events.EventLike');
/**
* goog.events.Event no longer depends on goog.Disposable. Keep requiring
* goog.Disposable here to not break projects which assume this dependency.
* @suppress {extraRequire}
*/
goog.require('goog.Disposable');
goog.require('goog.events.EventId');
/**
* A typedef for event like objects that are dispatchable via the
* goog.events.dispatchEvent function. strings are treated as the type for a
* goog.events.Event. Objects are treated as an extension of a new
* goog.events.Event with the type property of the object being used as the type
* of the Event.
* @typedef {string|Object|goog.events.Event|goog.events.EventId}
*/
goog.events.EventLike;
/**
* A base class for event objects, so that they can support preventDefault and
* stopPropagation.
*
* @suppress {underscore} Several properties on this class are technically
* public, but referencing these properties outside this package is strongly
* discouraged.
*
* @param {string|!goog.events.EventId} type Event Type.
* @param {Object=} opt_target Reference to the object that is the target of
* this event. It has to implement the {@code EventTarget} interface
* declared at {@link http://developer.mozilla.org/en/DOM/EventTarget}.
* @constructor
*/
goog.events.Event = function(type, opt_target) {
/**
* Event type.
* @type {string}
*/
this.type = type instanceof goog.events.EventId ? String(type) : type;
/**
* TODO(tbreisacher): The type should probably be
* EventTarget|goog.events.EventTarget.
*
* Target of the event.
* @type {Object|undefined}
*/
this.target = opt_target;
/**
* Object that had the listener attached.
* @type {Object|undefined}
*/
this.currentTarget = this.target;
/**
* Whether to cancel the event in internal capture/bubble processing for IE.
* @type {boolean}
* @public
*/
this.propagationStopped_ = false;
/**
* Whether the default action has been prevented.
* This is a property to match the W3C specification at
* {@link http://www.w3.org/TR/DOM-Level-3-Events/
* #events-event-type-defaultPrevented}.
* Must be treated as read-only outside the class.
* @type {boolean}
*/
this.defaultPrevented = false;
/**
* Return value for in internal capture/bubble processing for IE.
* @type {boolean}
* @public
*/
this.returnValue_ = true;
};
/**
* Stops event propagation.
*/
goog.events.Event.prototype.stopPropagation = function() {
this.propagationStopped_ = true;
};
/**
* Prevents the default action, for example a link redirecting to a url.
*/
goog.events.Event.prototype.preventDefault = function() {
this.defaultPrevented = true;
this.returnValue_ = false;
};
/**
* Stops the propagation of the event. It is equivalent to
* {@code e.stopPropagation()}, but can be used as the callback argument of
* {@link goog.events.listen} without declaring another function.
* @param {!goog.events.Event} e An event.
*/
goog.events.Event.stopPropagation = function(e) {
e.stopPropagation();
};
/**
* Prevents the default action. It is equivalent to
* {@code e.preventDefault()}, but can be used as the callback argument of
* {@link goog.events.listen} without declaring another function.
* @param {!goog.events.Event} e An event.
*/
goog.events.Event.preventDefault = function(e) {
e.preventDefault();
};