devlibx
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JavaScript
/*
* @Author: Peng Xiang (Email:px.i@foxmail.com QQ:245803627)
* @Date: 2024-08-20 16:20:43
* @LastEditTime: 2024-08-20 16:37:41
* @LastEditors: 彭祥
* @Description:
*
*/
/**
* https://github.com/mrdoob/eventdispatcher.js/
*/
class EventDispatcher {
addEventListener( type, listener ) {
if ( this._listeners === undefined ) this._listeners = {};
const listeners = this._listeners;
if ( listeners[ type ] === undefined ) {
listeners[ type ] = [];
}
if ( listeners[ type ].indexOf( listener ) === - 1 ) {
listeners[ type ].push( listener );
}
}
hasEventListener( type, listener ) {
if ( this._listeners === undefined ) return false;
const listeners = this._listeners;
return listeners[ type ] !== undefined && listeners[ type ].indexOf( listener ) !== - 1;
}
removeEventListener( type, listener ) {
if ( this._listeners === undefined ) return;
const listeners = this._listeners;
const listenerArray = listeners[ type ];
if ( listenerArray !== undefined ) {
const index = listenerArray.indexOf( listener );
if ( index !== - 1 ) {
listenerArray.splice( index, 1 );
}
}
}
dispatchEvent( event ) {
if ( this._listeners === undefined ) return;
const listeners = this._listeners;
const listenerArray = listeners[ event.type ];
if ( listenerArray !== undefined ) {
event.target = this;
// Make a copy, in case listeners are removed while iterating.
const array = listenerArray.slice( 0 );
for ( let i = 0, l = array.length; i < l; i ++ ) {
array[ i ].call( this, event );
}
event.target = null;
}
}
}
export { EventDispatcher };