ES6 class variable alternatives

Question

Currently in ES5 many of us are using the following pattern in frameworks to create classes and class variables, which is comfy:

Answer 1

[Long thread, not sure if its already listed as an option...].
A simple alternative for contsants only, would be defining the const outside of class. This will be accessible only from the module itself, unless accompanied with a getter.
This way prototype isn't littered and you get the const.

// will be accessible only from the module itself
const MY_CONST = 'string'; 
class MyClass {

    // optional, if external access is desired
    static get MY_CONST(){return MY_CONST;}

    // access example
    static someMethod(){
        console.log(MY_CONST);
    }
}