I just published an open-source repository that solves this problem:

- Converts Markdown to WhatsApp's format - Intelligently splits long texts into shorter fragments (without cutting lists, links, emails, and with syntax understanding) - Supports tables, so they look good - Runs 100% locally in your project, doesn't use external libraries, and has 100% test coverage

You can start using it with a simple 'npm install'.

If you find it useful, I'd appreciate it if you gave the repo a star :

https://github.com/daviddominguezh/llm-markdown-whatsapp