babel.config.json

{
  "babelrc": false,
  // Note: order is bottom-to-top and/or right-to-left
  "presets": [
    [
      "@babel/preset-env",
      {
        "bugfixes": true,
        "browserslistEnv": "dev",
        "useBuiltIns": "entry",
        "corejs": "3.10"
      }
    ],
    [
      "@babel/preset-typescript",
      {
        "allowNamespaces": true,
        "allowDeclareFields": true
      }
    ],
    [
      "@babel/preset-react",
      {
        "runtime": "automatic"
      }
    ]
  ],
  "plugins": [
    [
      "@babel/plugin-transform-typescript",
      {
        "allowNamespaces": true,
        "allowDeclareFields": true
      }
    ],
    // added to mitigate https://github.com/babel/babel/issues/14289
    // package (and following line) can be removed once the issue is fixed and released
    "@babel/plugin-proposal-class-properties",
    ["@babel/plugin-proposal-object-rest-spread", { "loose": true }],
    "@babel/plugin-transform-react-constant-elements",
    "@babel/plugin-proposal-nullish-coalescing-operator",
    "@babel/plugin-proposal-optional-chaining",
    "@babel/plugin-syntax-dynamic-import", // needed for `() => import()` in routes.ts
    "angularjs-annotate",
    "macros"
  ],
  "env": {
    "production": {
      "presets": [
        [
          "@babel/preset-env",
          {
            "browserslistEnv": "production"
          }
        ]
      ]
    },
    "hot": {
      "plugins": ["react-refresh/babel"]
    }
  }
}