I saw this post What is the easiest way to disable/enable buttons and links (jQuery + Bootstrap)
And I really like this:
// Disable function
jQuery.fn.extend({
    disable: function (state) {
        return this.each(function () {
            this.disabled = state;
        });
    }
});
My question is how would I avoid extending $ (or a custom namespace for that matter)
See for ref also:
https://api.jquery.com/jquery.extend/
I'm looking for safety checks when using extend when it's not needed because obj has already been extended, this to improve performance.