Question

Suppose I have a obj called myObj and it has a function test

MyObj.prototype.test = function(){
     alert(this);
}

And I set the timer:

setInteravl(myObj.test,1000);

As this depends entirely on how you called the function, this refers to window instead of myObj in the alert statement

What should I do if I need the myObj reference instead?

Answer 1

Wrap it in an anonymous function:

var myObj = new MyObj();

setInterval(function() {myObj.test();}, 1000);

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Or in modern implementations, bind it.

var myObj = new MyObj();

setInterval(myObj.test.bind(myObj), 1000);