Use `fs/promises` to work with files without blocking the event loop, validate paths defensively, and handle common file-system failures as expected cases instead of surprises.
Readable async flows and explicit error handling matter more than one-line convenience.
The `fs/promises` API fits naturally with `async/await` and keeps file work aligned with the asynchronous model of Node.
That is especially important in backend contexts, where synchronous file reads can block other useful work.
Never assume a path built from external input is harmless.
When a path comes from a request, CLI argument, or upload workflow, you should normalize and resolve it before trusting it.
The practical goal is to avoid directory traversal and to keep file operations inside an allowed working area.
Missing files and permission failures should be handled, not treated like rare accidents.
A file may not exist. A directory may be passed where a file is expected. Permissions may block access in production even if your local machine works.
When you recognize those failures clearly, your scripts become more stable and your error messages become more useful.
File access appears in more places than beginners expect.
Export jobs, report generation, local caches, configuration loading, import tools, and background jobs all rely on file I/O patterns like these.
If you can read and write files safely, you gain a practical bridge between JavaScript logic and the operating system around it.