fs-extra
fs-extra contains methods that aren't included in the vanilla Node.js fs package. Such as recursive mkdir, copy, and remove.
chokidar
Minimal and efficient cross-platform file watching library
globby
User-friendly glob matching
braces
Bash-like brace expansion, implemented in JavaScript. Safer than other brace expansion libs, with complete support for the Bash 4.3 braces specification, without sacrificing speed.