text: import {legacyPlugin} from '@web/dev-server-legacy';
  
  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: [
      legacyPlugin({
        polyfills: {
          // Manually imported in index.html file
          webcomponents: false,
        },
      }),
    ],
  };
  