Use of .apply() with 'new' operator. Is this possible?

Question

In JavaScript, I want to create an object instance (via the new operator), but pass an arbitrary number of arguments to the constructor. Is this possible?

Answer 1

This answer is a little late, but figured anyone who sees this might be able to use it. There is a way to return a new object using apply. Though it requires one little change to your object declaration.

function testNew() {
    if (!( this instanceof arguments.callee ))
        return arguments.callee.apply( new arguments.callee(), arguments );
    this.arg = Array.prototype.slice.call( arguments );
    return this;
}

testNew.prototype.addThem = function() {
    var newVal = 0,
        i = 0;
    for ( ; i < this.arg.length; i++ ) {
        newVal += this.arg[i];
    }
    return newVal;
}

testNew( 4, 8 ) === { arg : [ 4, 8 ] };
testNew( 1, 2, 3, 4, 5 ).addThem() === 15;

For the first if statement to work in testNew you have to return this; at the bottom of the function. So as an example with your code:

function Something() {
    // init stuff
    return this;
}
function createSomething() {
    return Something.apply( new Something(), arguments );
}
var s = createSomething( a, b, c );

Update: I've changed my first example to sum any number of arguments, instead of just two.