Question

I want to do this:

var person = {
    name: "John",
    __test__: (function() {alert(this.name)})()
}

but this.name is undefined. How to have its value then ?

Update: to make more sense, I rather want to do this ie auto-inialisation:

var person = {
    name: "",
    __test__: (function() {name = "john"})()
}`

‘John’ can come in real world from a mockup object, a database whatever, my point is I want to do this in a SELF-CONTAINED way not call test from an external object.

Answer 1

You can’t do this using an Object literal. this is referring to person after the literal is evaluated, during evaluation this refers to the parent scope. You could wrap the object construction in a function to be sure this refers to the current scope (i.e. the scope of the function). Something like:

var person = function(){
    this.name = 'John';
    this.__test__ = (function(){alert(this.name);}());
    return this;
}();

Or using variables within the function scope:

var person = function(){
    var _name = 'John'
        ,_test = (function(){alert(_name);}());
    return { name: _name, __test__: _test };
}();

Or wrap things in a more generic factory function:

function objFactory(obj){
    var nwObj = {};
    for (var l in obj){
        if (obj.hasOwnProperty(l)){
            if (obj[l] instanceof Function && /^auto_/i.test(l)){
             nwObj[l.replace(/^auto_/i,'')] = obj[l].call(nwObj);
            }
            else {
             nwObj[l] = obj[l];
            }
        }
    }
   return nwObj;
}
//=> usage
var person = objFactory(
               { name: '', 
                 auto_name: function(){
                             this.name='John'; 
                             return this.name;
                            }
                }
             );
 alert(person.name); //=> John

And finally (not everyone will agree to this) you could create a load handler in Object.prototype:

Object.prototype.load = function(){
    for (var l in this){
        if (this.hasOwnProperty(l) 
            && this[l] instanceof Function 
            && /^auto_/i.test(l)) {
          this[l].call(this);
          delete this[l];
        }
    }
    return this;
}
//=> usage
var person = {
               name: '', 
               auto_name: function(){this.name='John';}
             }.load();
alert(person.name); //=> John