Skip to main content

Troubleshooting

EXPO_ROUTER_APP_ROOT not defined​

If you see an error like this:

Invalid call at line 11: process.env.EXPO_ROUTER_APP_ROOT First argument of require.context should be a string.

It is because process.env.EXPO_ROUTER_APP_ROOT is not defined. This can happen when:

  • The project is using an expo version lower than expo@^46.0.13. The version 46.0.13 enables context modules and injects process.env.EXPO_ROUTER_APP_ROOT into the process.
  • The babel plugin expo-router/babel is not being used in the project babel.config.js. You can try clearing the cache with npx expo start --clear.

Alternatively you can circumvent this issue by creating an index.js file in the root of your project with the following contents:

import { registerRootComponent } from "expo";
import { ExpoRoot } from "expo-router";

// Must be exported or Fast Refresh won't update the context
export function App() {
  const ctx = require.context("./app");
  return <ExpoRoot context={ctx} />;
}

registerRootComponent(App);

Do not use this to change the root directory (app) as it won't account for usage in any other places.

require.context not enabled​

  • This can happen if you are using an expo version lower than expo@^46.0.13. The version 46.0.13 enables context modules and injects process.env.EXPO_ROUTER_APP_ROOT into the process.
  • This can also be the result of using a custom version of @expo/metro-config that does not enable context modules.
  • Expo Router requires the project metro.config.js file to use expo-router/metro as the default configuration. Delete the metro.config.js file, or extend expo/metro-config. Learn more