Reading the code in the wonderful Lawnchair library by Brian Leroux, the first thing I see is this great little pattern. All it does is make damn sure that 'new' is used to instantiate the object, as it must not be used as a Singleton.

Safe constructor

var YourObject = function () {
    
    // ensure YourCobject was called as a constructor
    if (!(this instanceof YourObject)) {
        return new YourObject();
    }

    // do your thing now, it's safe!!
};

Now I believe in throwing an Error instead and using a linter to yell at you.