Shipping Dual ESM/CJS in 2026: The Library Author Checklist
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Book: TypeScript in Production — Tooling, Build, and Library Authoring Also by me: The TypeScript Library — the 5-book collection My project: Hermes IDE | GitHub — an IDE for developers who ship with Claude Code and other AI coding tools Me: xgabriel.com | GitHub You publish a small utility package. It compiles. The README example runs on your laptop. You npm publish and move on. A week later an issue lands. A user on a CommonJS project imports your package, and their bundler pulls