Parent object reference

Question

I think I may be missing something coming to object reference, in the below case, is this refering to the test object? If not how can I declare b so in the end test.a = test.b ?

test = {
 a: 1,
 b: this.a,
 check : function(){
 console.log(test.a); // returns 1
 console.log(test.b); // returns undefined
 }
};
test.check();

Thanks a lot

Answer 1

You can declare it like this:

function test(){
 this.a = 1;
 this.b = this.a;
 this.check = function(){
 console.log(this.a); // output 1
 console.log(this.b); // output 1
 } 
}
var t = new test();
t.check();

Live example: http://jsfiddle.net/Rqs86/

• Gurpreet Singh: new is keyword here. You need to create a new instance of test constructor in order to get desired output.
• Dave Loepr: So if i get it correctly, you can not reference an object property declared within the same object scope level. I take this for solution, even if not, and Thank you for the demo aswell :)

Answer 2

test.b refers to whatever this.a was when declaring the object.

var foo = this;

You wouldn't expect this to refer to foo here, right? It works exactly the same here:

var bar = [ this ];

and

var baz = { 'blag' : this };

• Dave Loepr: Thanks, this is useful to understand why this refers to nuts when b is declared. But then, how can i get b to build itself on top of a, basically a is a jquery object, and b is a property of this object. a: $('.class'), b:a.css() for example.
• deceze: See @Jamiec's answer. Use a function which evaluates this at call time, not at declaration time.
• Dave Loepr: Working too much with jquery the difference between declaration time and call time can seem blurry ;)