JavaScript has turned out to be a powerful language with some unique features that enable efficient yet maintainable programming. Its closure pattern and event-driven behavior have proven to be very helpful in real-life scenarios, but like all programming languages, it isn't perfect, and one of its major design flaws is the sharing of a single global namespace.

To understand the problem, we need to go back to JavaScript's browser origins. In the browser, when you load a script into your web page, the engine will inject its code into an address space that is shared by all the other scripts. This means that when you assign a variable in one script, you can accidently overwrite another variable already defined in a previous script. While this could work with a small code base, it can easily cause conflicts in larger applications, as errors will be difficult to trace. It could have been a major threat for Node.js evolution as a platform, but luckily a solution was found in the CommonJS...