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

Suppose you've got an Items constructor which slurps up all the arguments you throw at it:

function Items () {
    this.elems = [].slice.call(arguments);
}

Items.prototype.sum = function () {
    return this.elems.reduce(function (sum, x) { return sum + x }, 0);
};

You can create an instance with Object.create() and then .apply() with that instance:

var items = Object.create(Items.prototype);
Items.apply(items, [ 1, 2, 3, 4 ]);

console.log(items.sum());

Which when run prints 10 since 1 + 2 + 3 + 4 == 10:

$ node t.js
10