Simplest/Cleanest way to implement singleton in JavaScript?

Question

What is the simplest/cleanest way to implement singleton pattern in JavaScript?

Answer 1

I needed several singletons with:

• lazy initialisation
• initial parameters

and so this was what I came up with:

createSingleton ('a', 'add', [1, 2]);
console.log(a);

function createSingleton (name, construct, args) {
    window[name] = {};
    window[construct].apply(window[name], args);
    window[construct] = null;
}

function add (a, b) {
    this.a = a;
    this.b = b;
    this.sum = a + b;
}

• args must be Array for this to work so if you have empty variables, just pass in []

• I used window object in the function but I could have passed in a parameter to create my own scope

• name and construct parameters are only String for window[] to work but with some simple type-checking, window.name and window.construct are also possible.