javascript final method

Question

Can a method in javascript be final? How to avoid it to be overriden by a subclass?

Answer 1

In the traditional sense, no, you can't have private/protected methods or prevent them from being overridden.

What you can do, however, is encapsulate methods in a scope and then simply not expose them:

function foo(){
    function bar(){
        // private function
    }

    this.doSomething = function(){
        bar();
    }
}

That's about as close as you can get. I wrote an article on this a while ago: http://www.htmlgoodies.com/primers/jsp/article.php/3600451/Javascript-Basics-Part-8.htm

You can also use __defineGetter__ and __defineSetter__ to prevent access, but those aren't 100% cross-browser.

var x = {};
x.__defineGetter__('foo', function(){ return 10; });
x.__defineSetter__('foo', function(){});

x.foo = 'bar';
x.foo; // 10