legacy-vite.config.ts

import externalGlobals from 'rollup-plugin-external-globals';

const externals = {
  react: 'React',
  'react-dom': 'ReactDOM',
  axios: 'axios',
};

export default defineConfig({
  ...
  plugins: [
    legacy({
      targets: {
        ie: '11'
      },
      polyfills: ['es/promise', /* ... */],
      additionalLegacyPolyfills: ['regenerator-runtime/runtime']
    }),
    externalGlobals(externals),
  ]
});