Description

When using h3-js in an ESM bundler environment (e.g., Nitro/Rollup for Vercel serverless), the build fails with:

ReferenceError: __dirname is not defined in ES module scope

Cause

The compiled out/libh3.js (Emscripten output) references __dirname for Node.js environment detection and file path resolution. This works in CommonJS but fails in ES modules where __dirname doesn't exist.

Environment

• Bundler: Rollup (via Nitro)
• Target: Vercel serverless (ESM)
• h3-js version: 4.4.0