To use the Stack class created previously, you would have to make a minor change to allow the stack to be used based on the environment in which you are planning to use it. Making this change generic is fairly straightforward; that way, you do not need to worry about multiple environments to support and can avoid repetitive code in each application:

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

    define(function () { return Stack; });

// NodeJS/CommonJS

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

    if (typeof module === 'object' && typeof module.exports ===
    'object') {

        exports = module.exports = Stack;
    }

// Browser

} else {

    window.Stack = Stack;
}

Once we add this logic to the stack, it is multi-environment ready. For the purpose of simplicity and brevity, we will not add it everywhere we see the stack; however, in general, it's a good thing to have in your code.