C# 的Timer 在javascript中的实现--基于Typescript

class Timer {

//js 内置的timer对象
    private _jsInnerTimerObj: any;
    private _enable: boolean;
    private _handlerInvoker:any;

    private _interval: number;

    get Interval(): number{
        return this._interval;
    }
    set Interval(value: number) {
        this._interval = value;
        //重新设定新的定时器
        if (this._jsInnerTimerObj) {
            window.clearInterval(this._jsInnerTimerObj);
        }

    }

    private _elapsed:any;

    get Elapsed(): any{
        return this._elapsed;
    }
    set Elapsed(value: any) {
        /*if (!isFunction(value)) {
            throw new Error("the Elapsed value must be function!");
        }*/
        this._elapsed = value;
        //只有设置了触发事件才定时，没有回调的定时器是无意义的定时执行其中的匿名方法
        this._jsInnerTimerObj = window.setInterval(this._handlerInvoker, this.Interval);     

    }

    /*  构造函数
    *@interval 设置定时器的毫秒数
    */
    constructor(interval: number) {
        this._enable = false;
        this.Interval = interval;
        var that = this;
        this._handlerInvoker = function () {
             if (that.Elapsed&&that._enable==true){
                that.Elapsed();
             }
        }
    }

    Start() {
        this._enable = true;
    }
    Stop() {
        this._enable = false;
    }
}

var t = new Timer(500);
t.Elapsed = function () {
   document.write(99)
}
t.Start();