module.exports = {
  presets: [
    ['@vue/app', {
      // polyfills: [
      //   'es6.promise',
      //   'es6.symbol',
      //   'es6.array.iterator',
      //   'es6.object.assign'
      // ],
      useBuiltIns: 'entry'
    }
    // '@vue/cli-plugin-babel/preset'
    ]
  ],
  // presets: [
  //   '@vue/cli-plugin-babel/preset',
  //   ['@babel/preset-env', {
  //     useBuiltIns: 'entry',
  //     corejs: 3
  //   }]
  // ],
  // presets: [['@vue/cli-plugin-babel/preset', { useBuiltIns: 'entry' }]], // 此为vue/cli4
  // presets: [
  //   '@vue/cli-plugin-babel/preset'
  // ],
  env: {
    development: {
      // babel-plugin-dynamic-import-node plugin only does one thing by converting all import() to require().
      // This plugin can significantly increase the speed of hot updates, when you have a large number of pages.
      // https://panjiachen.github.io/vue-element-admin-site/guide/advanced/lazy-loading.html
      plugins: ['dynamic-import-node']
    }
  }
}