astro/packages/renderers/renderer-react/index.js

export default {
  name: '@astrojs/renderer-react',
  client: './client.js',
  server: './server.js',
  jsxImportSource: 'react',
  jsxTransformOptions: async () => {
    const {
      default: { default: jsx },
    } = await import('@babel/plugin-transform-react-jsx');
    return {
      plugins: [jsx({}, { runtime: 'automatic', importSource: 'react' })],
    };
  },
  viteConfig() {
    return {
      optimizeDeps: {
        include: ['@astrojs/renderer-react/client.js', 'react', 'react/jsx-runtime', 'react/jsx-dev-runtime', 'react-dom'],
        exclude: ['@astrojs/renderer-react/server.js'],
      },
      resolve: {
        dedupe: ['react', 'react-dom'],
      },
      ssr: {
        external: ['react-dom/server.js'],
      },
    };
  },
};