js.next-classes.js

// From: https://mail.mozilla.org/pipermail/es-discuss/2011-October/thread.html#17696

const className = superClass <| function(/*constructor parameters */) {
    //constructor body
    super.constructor(/*arguments to super constructor */);
    this.{
     //per instance property definitions
    };
}.prototype.{
    //instance properties defined on prototype
}.constructor.{
    //class (ie, constructor) properties
};

@addyosmani: All of the various class libraries work more or less the same way, with different levels of extra features. Resig's simple inheritance is about as minimal as it gets, whereas JS.Class has all kind of extra hooks and goodies in it.

CoffeeScript's classes are just simple proper prototype chain inheritance, combined with sugar for easily calling super. The main bonus feature that isn't (and can't be) mimicked in a JavaScript library is executable class bodies.