pedroslopez/whatsapp-web.js — reverse-engineered prompt

Build me a Node.js library that lets developers control WhatsApp through WhatsApp Web, like a simple unofficial API. It should open and manage a browser session, show a QR code for login, remember the session when possible, and let code listen for incoming messages and reply to them.

I want it to support normal WhatsApp actions such as sending text, media, stickers, contacts, locations, reactions, polls, and working with groups, including invites, members, subjects, descriptions, permissions, mentions, mute, block, and contact info. Include a clear example that replies pong when someone sends !ping.

Please make it feel like a real reusable package, with docs, examples, sensible events, and helpful error messages. It should work on modern Node.js and explain any browser or Chrome requirements for media. Also include a clear warning that this is not official WhatsApp software and that using it could risk the account being blocked.