Coping with JavaScript cross-Runtime Incompatibilities

Moving from Node.js to Bun, Cloudflare Workerd, or Vercel Edge sounds straightforward until your database driver stops working or your markdown library throws at import time. The JavaScript runtime landscape has fragmented, and most popular packages were never tested beyond Node.

I shared firsthand experience refactoring libraries to support Cloudflare Workers and Bun: which incompatibilities bite hardest, how to detect them early, and what the open-source community can do to reduce this friction long-term.