Use modules to separate responsibilities and make dependencies explicit in a growing JavaScript project.
The core idea
Modules allow code to export functions and values and import them where needed. Clear module boundaries reduce global variables and help readers understand which parts depend on one another.
A practical way to approach it
Move one cohesive responsibility into a module, export a small public API, and import it where used. Keep browser and server module conventions consistent with your project’s tooling.
Try it in a small project
Move form validation and formatting helpers out of a large page script. Test the helpers independently and keep DOM manipulation in the UI layer.
Common mistakes to avoid
Do not create one module per tiny function without a clear boundary. Watch for circular imports and avoid mixing secrets into client-side modules.
Key takeaway
Keep the first version small, make your assumptions explicit, and verify the result with a repeatable test. For production use, check the current official documentation for the tools and versions you choose.