Question

Is there a function like super when you are modifying a prototype in javascript?

Answer 1

Not in the language itself — but there is no reason you cannot add it when you are creating your class. There is actually a very nice exposition on the way that Coffeescript manages prototypal inheritance by Justin Reidy on his blog

The key part is reproduced here:

var __hasProp = Object.prototype.hasOwnProperty;
function __extends(child, parent) {
    for (var key in parent) { 
        if (__hasProp.call(parent, key)) {
            child[key] = parent[key];
        }
    }
    function ctor() { this.constructor = child; }
    ctor.prototype = parent.prototype;
    child.prototype = new ctor;
    child.__super__ = parent.prototype;
    return child;
}

You will also probably want to read @bobince’s introduction to working with classes in JavaScript.