setTimeout（）在JavaScript类中使用“this” [英] setTimeout() inside JavaScript Class using "this"

问题描述

我试图在JavaScript中的类函数中使用 setTimeout（）。 setTimeout（）应该在同一个类中触发另一个方法，所以我传递的函数写为 window.setTimeout（this .anotherMethod，4000）。这带来了问题： this 引用调用对象，在 setTimeout（）的情况下，它是窗口。如何使用附件来返回类对象本身的引用？

  myObject = function（）{
 
 this.move = function（）{
 alert（this +is running）; 
} 
 this.turn = function（）{
 alert（this +is turning）; 
} 
 this.wait = function（）{
 window.setTimeout（this.run，（1000 * randomNumber（1,5）））; 
} 
 
 this.run = function（）{
 switch（randomNumber（0,2））{
 case 0：
 this.move ）; 
 break; 
 case 1：
 this.turn（）; 
 break; 
 case 2：
 this.wait（）; 
} 
} 
  

}

  var that = this; 
 setTimeout（function（）{
 that.doStuff（）; 
}，4000）; 
  

您还可以 bind 以获得更简洁的代码（如@Raynos最初指出的） p>

  setTimeout（this.doStuff.bind（this），4000）; 
  

bind 此编码模式（即捕获此词法）。

I am trying to use setTimeout() inside a class function in JavaScript. The setTimeout() is supposed to trigger another method in the same Class, so the function I am passing it is written as window.setTimeout("this.anotherMethod", 4000). That bring the problem: this references the calling Object, in the case of setTimeout() it is window. How can I use enclosures to return a reference to the Class Object itself?

myObject = function(){

this.move = function(){
    alert(this + " is running");
}
this.turn = function(){
    alert(this + " is turning");
}
this.wait = function(){
    window.setTimeout("this.run" ,(1000 * randomNumber(1,5)));
}

this.run = function(){
    switch(randomNumber(0,2)){
        case 0:
            this.move();
        break;
        case 1:
            this.turn();
        break;
        case 2:
            this.wait();
    }
}

}

解决方案

You can do this:

 var that = this;
 setTimeout(function () {
     that.doStuff();
 }, 4000);

You can also bind for more succinct code (as originally pointed out by @Raynos):

setTimeout(this.doStuff.bind(this), 4000);

bind is a standard library function for exactly this coding pattern (ie capturing this lexically).

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