From CommonJS Spec Wiki
There are a variety of ways to transport a module from a server to a browser. However, the highest performance solutions available today involve script injection, which necessitates that the script arrange with the loader to call a particular function when it executes.
- Modules/Transport/A "run" system.
- Modules/Transport/B "register" system.
- Modules/Transport/C "register" system that uses positional args, explicit free variables.
- Modules/Transport/D "register" system that supports dependency injection and module sets.