clone for @JeremiePat

c.js

var obj = {
   a: 1,
   get b(){ return 2 },
   c: 3
}

Object.defineProperty(obj, 'c', {configurable: false, writable: false});

function clone(o){
    var c = Object.create(Object.getPrototypeOf(o));

    Object.getOwnPropertyNames(o).forEach(function(p){
        Object.defineProperty(c, p, Object.getOwnPropertyDescriptor(o, p));
    })

    return c;
}

console.log(clone(obj))