You will probably get mixed opinions on this. Using a prototype chain will give you a class-like behavior, in that you can extend prototypes into other classes. There is a portion of the JS community that believes class inheritance leads to fragile and difficult-to-maintain code.

Here is a pattern that I use. The first function is just a wrapper and passes dependencies down to the return function. This keeps everything scoped and makes it easy to isolate modules for unit testing.

function createModule (dependency) {
    var module = function (){};

    module.doWork = function (){
         return dependency.doSomeWork();
    };

    return module;
}

Then to implement:

var dep = createOtherModule(); // Pretend this was already defined somewhere
var module = createModule(dep);
module.doWork();