Idea to make private properties and methods non-enumerable instead of prefixing them with underscores (in ES5 and above environments of course)

hidepatch.js

Object.defineProperty(Object.prototype, "hide", {
  value: function () {
    [].forEach.call(arguments, function (name) {
      var descriptor = Object.getOwnPropertyDescriptor(this, name);
      if (descriptor.enumerable) {
        descriptor.enumerable = false;
        Object.defineProperty(this, name, descriptor);
      }
    }, this);
  }
});

function Rectangle(w, h) {
  this.w = w;
  this.h = h;
  // For some reason, we want "w" and "h" to be private properties
  this.hide("w", "h");
}

Rectangle.prototype.privateMethod = function () {};
Rectangle.prototype.hide("privateMethod");

@creationix:

I can think of a couple special case uses for this. Just glancing at it, I was wondering if this wouldn't be safer if line 5 were instead:

if (descriptor.enumerable && descriptor.configurable) {