`commander-completion` is a small Node.js library that augments Commander.js CLI programs with Bash‑style tab‑completion. It provides a mixin that adds `.completion()` and `.complete()` methods so developers can supply custom async callbacks (e.g., fetching git branches) and expose a `completion` command that Bash can invoke to suggest possible sub‑commands or options. The package is aimed at developers building command‑line tools with Commander.js who want native shell completion support.