Javascript object scope

Question

How do I access the "a" below?

var test = function () {
     return {
        'a' : 1,
        'b' : this.a + 1  //doesn't work
    };
};

Answer 1

You cannot do this. When you are in the process of constructing an object (what you are actually using with curly curly braces), there is no way to access its properties before creating it.

var test = function () {
  var o = {};
  o['a'] = 1;
  o['b'] = o['a'] + 1;
  return o;
};

Answer 2

var t = function () 
        {
            return new x();
        };

var x = function ()
        {
            this.a = 1;
            this.b = this.a + 1; //works
        }

abstract layer

edited for formatting, and noting that this is an offset from OLN

Answer 3

You cannot Object Literal Notion does not support this access

Answer 4

var test = function () {
    //private members
    var a = 1;
    var b = a + 1;
    //public interface
    return {
        geta : function () {
            return a;
        },
        getb : function () {
            return b;
        }
    }
}();