Testing a private prototype method in JS

Question

I was wondering if it was possible to test a private method of a prototype in js. I suspect it's impossible but maybe someone would surprise me...

For example, suppose I have the following class restaurant:

function Restaurant() {
}

Restaurant.prototype = (function() {
    var private_stuff = function() {
    // Private code here
    };

    return {

        constructor:Restaurant,

        use_restroom:function() {
            private_stuff();
        }

    };
})();

Would it be possible to write a unit test for private_stuff method? I use jasmine for my unit tests, but I guess it doesn't really matter.

Thanks, Lior

Answer 1

The last time I faced something similar, I had to specifically expose private stuff, as odd as that sounds:

function Restaurant() {
}

Restaurant.prototype = (function() {
    var private_stuff = function() {
    // Private code here
    };

    var internalMethods = {};
    if (window.exposeInteralMethods) {
      internalMethods = {
        private_stuff: private_stuff
      };
    }

    return {   
        internalMethods: internalMethods,
        constructor:Restaurant,    
        use_restroom:function() {
            private_stuff();
        }

    };
})();

You are at risk if anyone sets window.exposeInteralMethods besides you, but sometimes one needs 2x4 debugging of the squirmware.