Holy shit private members!

es6.js

var foo = Symbol('foo');

class MyClass {
  constructor() {
    // Calling a private method!!!
    this[foo]();
  }
  
  [foo]() {
    alert('FOOOOOO!!!!!!');
  }
}

// Cannot call private method!!! Throws!
var myClass = new MyClass();
myClass.foo();

override.js

class BaseStore {
  get(id) {
    // return a single record...
  }
  
  [Symbol.for('store.insert')](record) {
    // insert a record
  }
}

class UsersStore extends BaseStore {

  // Override BaseStore's private "insert" method using namespaced
  // global symbols!
  [Symbol.for('store.insert')](user) {
    // Special logic when inserting user into store...
    super[Symbol.for('store.insert')](user);
  }
}

Now we can enforce the rule that consumers can only get data, and not manipulate data, on a store. Simultaneously we can provide basic functionality in a single base Store class, and extend/override for custom use cases.

This all works via babel right now.