> For example, Javascript's objects are so lightweight that it's idiomatic to write them inline exactly where they're needed, like 'foo({bar: function() { ... }, ...})'.
Idiomatic doesn't mean maintainable and scalable. Imagine you are working on a project in a team, not alone. How do you understand what kind of "lightweight" object you should pass to this function:
function foo(data) { .. }
When you have thousands of such functions you'll spend most time reading through their code to understand what type of argument they need. This means "idiomatic" javascript code works only when it is small in size. Once it gets larger you'll have to resort to old school non-idiomatic Java-like classes and a static typing system.
Regarding prototypal inheritance I don't understand how it is supposed to be used. Let's say we have constructors for objects User(name) and SuperUser(name, privileges). I understand if `SuperUser` is inherited from `User` (class-based ineritance), but I don't understand what is the meaning of SuperUser being inherited from some user charlie. Why `charlie` and not `john`? Why do I need an instance of common `User` to create a `SuperUser`? And as I haven't seen the explanation in above comments I guess you don't understand it too yet evangelize about it.
I think JS was supposed not to have any inheritance at all. The objects were supposed to be created with constructors and that is all. As an argument I can say that a helper method `Object.create()` that is required for object inheritance was only added in ES5 [1] and haven't existed in earlier versions. This is how you create objects from objects without classes and even without constructors:
var person = { name: null, greet: function () { ... } };
var john = Object.create(person, { name: 'John' });
var charlie = Object.create(person, { name: 'Charlie' });
var superCharlie = Object.create(charlie, { isSuperUser: true });
I also guess JS doesn't have classes because it was designed for writing simple form validation scripts and not large applications.
[1] https://developer.mozilla.org/en-US/docs/Web/JavaScript/Refe...