src/EventListener.js

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/// @MIT-LICENSE | 1.0.0 | https://api.guless.com/
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import IEventListener from "./IEventListener";
import IEventListenerOptions from "./IEventListenerOptions";
import Event from "./Event";
import EventListenerOptions from "./EventListenerOptions";

/**
 * 定义 {@link EventDispatcher} 的事件侦听器对象。
 * @implements {IEventListener}
 * @since 1.0.0
 */
export default class EventListener /*< implement IEventListener >*/ {
    /**
     * 创建一个侦听器对象。
     * 
     * @param {Function|IEventListener} handler - 指定事件处理函数或者是一个侦听器。
     * @param {Boolean|IEventListenerOptions} [options=false] - 指定侦听器的配置选项。
     * @since 1.0.0
     */
    constructor( handler, options = false ) {
        /**
         * @type {Function|IEventListener}
         */
        this._handler = handler;
        
        /**
         * @type {EventListenerOptions}
         */
        this._options = (new EventListenerOptions()).initWithParams(options);
    }
    
    /**
     * 获取侦听器的处理函数。
     * @type {Function|IEventListener}
     * @since 1.0.0
     */
    get handler() {
        return this._handler;
    }
    
    /**
     * 获取侦听器的配置选项。
     * @type {EventListenerOptions}
     * @since 1.0.0
     */
    get options() {
        return this._options;
    }
    
    /**
     * 处理一个事件对象。
     * @param {Event} event - 指定派发的事件对象。
     * @since 1.0.0
     */
    handleEvent( event ) {
        if ( (typeof this._handler.handleEvent == "function") ) {
            this._handler.handleEvent(event);
        }
        
        else {
            this._handler.call(this._options.scope || event.currentTarget, event);
        }
    }
}