sindresorhus/meow

Meow is a small JavaScript library that makes it easier to build command-line tools for Node. When you write a program that runs in the terminal, you typically need to handle things like reading the options a user typed, showing a help message when they pass a flag like --help, and displaying the version number when they ask for it. Meow handles all of that for you. The main thing it does is parse command-line arguments. If a user runs your tool with flags like --rainbow or --count 5, Meow reads those values and hands them to your code in a clean object. It also automatically converts hyphenated flag names to camelCase, so a flag like --my-color becomes myColor in your code. Flags prefixed with --no- are treated as negations, so --no-color sets color to false. Meow also supports defining subcommands. If you are building a tool that has multiple modes, like run, list, or build, you can declare those commands and Meow will parse which one the user selected and pass along the remaining arguments. Setup is straightforward. You import the library, call it with a help text string and a configuration object defining your flags, and it returns an object containing the parsed input and flags. There are no dependencies, which keeps the install footprint minimal. The library is published by Sindre Sorhus, a prolific open-source JavaScript developer. It has been widely adopted in the Node ecosystem as a low-friction starting point for anyone writing a command-line application.