Browserify universal module definition - browser/node different dependencies

How is it best to setup my UMD to inject different dependencies based on if its being run in a node or a browser environment?

I have the following UMD for my module which should work in both browser and node environments. I am struggling however because Node requires both the 'ws' and 'atob' dependencies whereas the browser doesn't.

Normally, the third condition would run here, but because I am using Browserify, the second condition is met...and the un-required dependencies are fetched.

(function (root, factory) {

    if (typeof define === 'function' && define.amd) {

        // AMD
        define(['q'], ['ws'], ['atob'], factory);

    } else if (typeof exports === 'object') {

        // Node OR Browserify
        module.exports = factory(require('q'), require('ws'), require('atob'));


    } else {

        // Browser globals (root is window) Q and WebSocket is already available
        Library = factory(root.Q, root.WebSocket, root.atob);

    }
}(this, function (Q, WebSocket, atob) {


     return {
         //stuff
     };

}));

Is it possible for Browserify to run the module definition as if it were a browser? In which case, I could use..

 typeof window === 'undefined'