astro/packages/renderers/renderer-preact/compat/index.js

export default {
  name: '@astrojs/renderer-preact/compat',
  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: 'preact/compat' })],
    };
  },
  viteConfig() {
    return {
      alias: {
        react: 'preact/compat',
        'react-dom': 'preact/compat'
      },
      resolve: {
        dedupe: ['react', 'react-dom'],
      },
      optimizeDeps: {
        include: ['@astrojs/renderer-preact/client.js', 'preact/compat', 'preact/compat/jsx-runtime', 'preact-render-to-string'],
      },
      ssr: {
        external: ['preact-render-to-string'],
      },
    };
  },
};