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();
}
}
}
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).