Learn how to split code into reusable files with `export` and `import`, avoiding hidden dependencies and improving maintainability, testing and scalability.
A module is not only a file. It is also a clear contract with the rest of the system.
Think of each module as a box with a public API. What you export is what other parts of the app are allowed to know about.
When you split code by domain such as formatting, validation, API or UI, maintenance depends less on personal memory.
Define what leaves the module and what enters from other modules.
Named exports are great when one file offers several utilities. Default exports are useful when the module revolves around one main entity.
The real benefit is explicit dependency reading: anyone opening the file can see what the module needs and what it offers.
Both are valid, but each one fits a different context.
Use named exports when a module exposes several utilities or when you want autocompletion and imports to stay more explicit.
Use a default export when the module represents one main thing, such as one central function or one class.