dthree/vorpal

Vorpal is a Node.js framework for building interactive command-line applications. Rather than a simple script that runs once and exits, a Vorpal app launches its own persistent prompt where users type commands and get responses, similar to how a shell like Bash works but built entirely within your application. You define commands with a short API: give a command a name, describe what arguments and options it accepts, and attach a function that runs when it is called. Vorpal handles the rest: it provides built-in help output, persistent command history, tab-based auto-completion (including custom completions per command), and the ability to pipe commands together. You can also define "modes" that change the prompt and behavior temporarily while the user is inside a particular workflow. The library is installed via npm and targets Node.js developers who want to ship a polished interactive tool rather than a flat script. A small ecosystem of community extensions adds features like paging output through a pager, importing new commands at runtime, or adding a built-in read-eval-print loop (REPL) to inspect state. The project notes that it is now in "open open source" mode: the original author is not actively maintaining it and is looking for volunteers to take over. This is worth knowing before adopting it for a production project, as it may not receive regular updates. The README includes a quick-start example that turns a plain Node file into a working CLI in about ten lines of code.