javascript-design-patterns | Classic design patterns in Javascript | Architecture library

I am trying to implement Singleton in JavaScript where I use Node.js module.export and require().

My issue is that module.export so far for me returns new object from a class.

If I make it so that all classes are only available requiring them from Singleton class and not require() - then would I guarantee that I will have one instance only?

Because if all Other classes import from Singleton - how should I import Singleton?

In php no matter how many instances of Singleton you have - each share static properties. So if you make the instance static then all Singleton's no matter in which files they are invoked have the same memory and perform the same action.

However I have no idea what is the case with JavaScript

I also have another approach - If I make let instance variable at the start of the file and check if its empty at the end and if it isn't I make another instance instance = new MyClass() and then module.export = instance. Would this give me the same result?

For example what I currently do