ES discussion on prototype focused classes.

current.js

function Foo(options) { .... }
Foo.prototype.do_foo_job = function()  { ... }

function Bar(options) {
    if (!(this instanceof Bar))
       return this new Bar(options);
    Foo.apply(this, arguments);
}
Bar.prototype = Object.create(Foo.prototype);
Bar.prototype.do_bar_job = function() { .... };

es-next.js

// Would be better if it was just Object
var Foo = Object.prototype <| {
  initialize (options) { ... },
 do_foo_job() { ... }
}

var Bar = Foo <| {
  do_bar_job() { ... }
}

prototype-focused.js

// Object.extend is just a proxy to Object.prototype.extend
var Foo = Object.extend({
   initialize: function(options) { ... },
   do_foo_job: function() { ... }
})

var Bar = Foo.extend({
    do_bar_job: function() { ... }
})