Babel Config Sample

Babel Configs

const babelServerConfig = {
  extensions: ['.js', '.mjs', '.html', '.ts'],
  babelHelpers: 'bundled',
  exclude: ['node_modules/@babel/**'],
  presets: [
    [
      '@babel/preset-env',
      {
        modules: false,
        targets: { node: 12 },
      },
    ],
    '@babel/preset-typescript',
  ],
  plugins: [
    '@babel/plugin-syntax-dynamic-import',
    '@babel/proposal-class-properties',
    '@babel/plugin-proposal-object-rest-spread',
    '@babel/plugin-proposal-nullish-coalescing-operator',
    '@babel/plugin-proposal-optional-chaining',
  ],
};

const babelClientConfig = {
  ...babelServerConfig,
  exclude: ['node_modules/@babel/**'],
  presets: [
    [
      '@babel/preset-env',
      {
         // won't run on IE11 but will on almost anything newer
        targets: { esmodules: true },
        // Or use this instead this to run on almost any browser
        // targets: '> 0.25%, not dead'
      },
    ],
    '@babel/preset-typescript',
  ],
};

Babel dependencies

"@babel/core": "^7.7.0",
"@babel/plugin-proposal-class-properties": "^7.7.0",
"@babel/plugin-proposal-nullish-coalescing-operator": "^7.4.4",
"@babel/plugin-proposal-object-rest-spread": "^7.6.2",
"@babel/plugin-proposal-optional-chaining": "^7.6.0",
"@babel/plugin-syntax-dynamic-import": "^7.2.0",
"@babel/preset-env": "^7.7.0",
"@babel/preset-typescript": "^7.7.0",
"@rollup/plugin-babel": "^5",