EventEmitter 事件式编程

EventEmitter.js

"use strict"
/**事件式编程 */
class EventEmiter {

    constructor(debug) {
        this._debuger_ = !!debug;
        this._callback_ = {};
        this.commonApi();
    }

    debug(info) {
        if (!this._debuger_) return;
        console.log(info);
    }

    /**
     * 事件监听
     * @param {string} ev 事件名称
     * @param {function} callback 回调函数
     */
    addListener(ev, callback) {
        this.debug(`Add listener for ${ev}`);
        this._callback_[ev] = this._callback_[ev] || [];
        this._callback_[ev].push(callback);
        return this;
    }

    /**
     * 移除事件监听
     * @param {string} ev 事件名称
     * @param {function} callback 回调函数
     */
    removeListener(ev, callback) {
        let calls = this._callback_;
        if (!ev) {
            this.debug('Remove all listeners');
            this._callback_ = {};
            return this;
        }
        if (!callback) {
            this.debug(`Remove all listeners of ${ev}`);
            calls[ev] = [];
            return this;
        }
        let list = calls[ev] || [];
        list.forEach((cb, index) => {
            if (cb === callback) {
                this.debug(`Remove all listeners of ${ev}`);
                list[index] = null;
            }
        });
        return this;

    }

    /**移除所有事件监听 */
    removeAllListeners(eventName) {
        this.removeListener(eventName);
    }

    /**
     * 事件触发器
     * @param {string} ev 事件名称
     * @param {*} data 数据
     */
    trigger(ev, data) {
        let list, callback, calls = this._callback_;
        if (!ev) return this;
        list = calls[ev] || [];
        list.forEach((cb, i) => {
            if (!(callback = cb)) {
                list.splice(i, 1);
            } else {
                let args = [];
                for (let j = 1; j <= arguments.length; j++) {
                    args.push(arguments[j]);
                }
                callback.apply(this, args);
            }
        });
        return this;
    }

    /**
     * 兼容使用习惯
     */
    commonApi() {
        this.fire = this.trigger;
        this.emit = this.trigger;
        this.bind = this.addListener;
        this.on = this.addListener;
        this.unon = this.removeListener;
        this.unbind = this.removeListener;
        this.unbindAll = this.removeAllListeners;
    }
}


module.exports = EventEmiter;