Passing a parameter as a pointer in JavaScript

Question

Take a look at the following code:

var o;

(function (p) {
    p = function () {
        alert('test');
    };
})(o);

o(); // Error: 'o is not a function'

In the above function I am creating an anonymous function that takes one parameter, which self-invokes with a previously-created object passed as a parameter. Then I am pointing this object to a function (from inside the new scope) and ultimately (trying) to invoke it from outside.

My question is, how can I pass that argument 'by reference' as to change the pointer it points to ?

Answer 1

You can achieve the effect you want by taking advantage of the fact that Javascript passes objects by reference:

var o = { };

(function (p) {
    p.fn = function () {
        alert('test');
    };
})(o);

o.fn();