Method unbind

src/common/overlay/levelRenderer/Eventful.js:112–139

* @function LevelRenderer.Eventful.prototype.unbind * @description 解绑事件。 * @param {string} event - 事件名。 * @param {boolean} handler - 响应函数。 * @returns {LevelRenderer.Eventful} this

(event, handler)

     * @returns {LevelRenderer.Eventful} this
     */
    unbind(event, handler) {
        var _h = this._handlers;

        if (!event) {
            this._handlers = {};
            return this;
        }

        if (handler) {
            if (_h[event]) {
                var newList = [];
                for (var i = 0, l = _h[event].length; i < l; i++) {
                    if (_h[event][i]['h'] != handler) {
                        newList.push(_h[event][i]);
                    }
                }
                _h[event] = newList;
            }

            if (_h[event] && _h[event].length === 0) {
                delete _h[event];
            }
        } else {
            delete _h[event];
        }

        return this;
    }


    /**