How to define private constructors in javascript?

Question

I have defined pure objects in JS which expose certain static methods which should be used to construct them instead of the constructor. How can I make a constructor for my

Answer 1

Simply don't expose the constructor function. The core issue with the original code is the "static method" is defined as a property of the constructor (which is used as a "class") as opposed a property of the module.

Consider:

return {
    mkNewScore: Score.mkNewScore
    // .. and other static/module functions
};

---

The constructor can still be accessed via .constructor, but .. meh. At this point, might as well just let a "clever user" have access.

return {
    mkNewScore: function (score) {
        var s = new Score(score, score >= 33);
        /* Shadow [prototype]. Without sealing the object this can
           be trivially thwarted with `del s.constructor` .. meh.
           See Bergi's comment for an alternative. */
        s.constructor = undefined;
        return s;
    }
};