setTimeout() inside JavaScript Class using "this"

Question

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();     } } 

}

Answer 1

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).

Answer 2

You can also bind a function to scope.

setTimeout(this.run.bind(this) ,(1000 * randomNumber(1,5)));

Be warned Function.prototype.bind is ES5