The **sanitize‑filename** package provides a small Node.js utility that cleans any string so it can be safely used as a file name on Windows, macOS, or Unix. It strips directory paths, control and reserved characters, Windows‑specific names, trailing spaces/periods, and enforces a 255‑byte limit, optionally allowing a custom replacement for removed characters—making it useful for developers who need to store user‑supplied or generated strings as files without risking invalid or unsafe filenames.