web-dev-server.config.js

import { fileURLToPath } from 'url';
import { esbuildPlugin } from '@web/dev-server-esbuild';

const mode = process.env.MODE || 'dev';
if (!['dev', 'prod'].includes(mode)) {
  throw new Error(`MODE must be "dev" or "prod", was "${mode}"`);
}

export default {
  nodeResolve: { exportConditions: mode === 'dev' ? ['development'] : [] },
  preserveSymlinks: true,
  plugins: [
    esbuildPlugin({
      ts: true,
      tsconfig: fileURLToPath(new URL('./tsconfig.json', import.meta.url)),
    }),
  ],
};