feat: Implement Mex (Meta Experiment) and Newsletter functionality from Baileys v7.0.0-rc.9

[alltomatos]

Mex (Meta Experiment) and Newsletter Implementation

This PR adds complete support for the Mex protocol and Newsletter functionalities, ported from Baileys v7.0.0-rc.9.

📋 Changes

New Files

• src/Types/Newsletter.ts: Complete Newsletter types, including QueryIds and XWAPaths for GraphQL queries
• src/Socket/mex.ts: Mex protocol implementation with executeWMexQuery function for GraphQL queries
• src/Socket/newsletter.ts: Extended socket with all Newsletter operations

Modified Files

• src/Types/index.ts: Newsletter types export
• src/Socket/index.ts: Changed to use makeNewsletterSocket as main socket

✨ Features

The Newsletter socket now provides:

Newsletter Management

• ✅ newsletterCreate: Create newsletter
• ✅ newsletterUpdate: Update metadata
• ✅ newsletterDelete: Delete newsletter
• ✅ newsletterMetadata: Get metadata by invite or JID

Interactions

• ✅ newsletterFollow / newsletterUnfollow: Follow/unfollow newsletters
• ✅ newsletterMute / newsletterUnmute: Mute/unmute notifications
• ✅ newsletterReactMessage: React to messages
• ✅ newsletterFetchMessages: Fetch messages
• ✅ subscribeNewsletterUpdates: Subscribe to live updates

Administrative Operations

• ✅ newsletterUpdateName / newsletterUpdateDescription / newsletterUpdatePicture: Update information
• ✅ newsletterRemovePicture: Remove picture
• ✅ newsletterAdminCount: Count administrators
• ✅ newsletterChangeOwner: Change owner
• ✅ newsletterDemote: Remove admin privileges
• ✅ newsletterSubscribers: Get subscriber count

🔧 Technical Details

Socket Chain

Newsletter → Business → Groups → Chats → Messages → Base

Implemented Fixes

• Proper type assertions in parseNewsletterMetadata for TypeScript strict mode compatibility
• Error handling with Boom for GraphQL responses
• Robust data path parsing in Mex responses

✅ Verification

• TypeScript compilation without errors
• Code ported directly from Baileys v7.0.0-rc.9
• Maintains compatibility with existing sockets
• All Newsletter operations implemented

📚 Usage Example

import { makeNewsletterSocket } from 'whaileys';

const sock = makeNewsletterSocket(config);

// Create newsletter
const newsletter = await sock.newsletterCreate('My Newsletter', 'Description');

// Follow newsletter
await sock.newsletterFollow(newsletter.id);

// Fetch messages
const messages = await sock.newsletterFetchMessages(newsletter.id, 10, 0, 0);

// React to message
await sock.newsletterReactMessage(newsletter.id, serverId, '👍');

🔗 References

• Based on: Baileys v7.0.0-rc.9
• Source files:
  • src/Types/Newsletter.ts
  • src/Socket/mex.ts
  • src/Socket/newsletter.ts

📊 Statistics

• Files changed: 5
• Lines added: 368
• Lines removed: 1

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This implementation brings complete parity with Baileys for Newsletter functionalities, allowing Whaileys-based applications to use all WhatsApp channels/newsletters features.