When you develop a NodeJS application, you probably get to work with services and as much as possible with service dependency injection.
As I worked quite a lot with Symfony lately, I wanted to be able to manage my NodeJS services as it should be, and in some case, like a database connection: a single instance for the whole script.

I quicky looked onto Internet to see how to build a singleton in JavaScript (pardon my weak skills in this language) and I quickly found what I was (almost) looking for.

Code examples provided in the different posts I've read