修改Android版本信息后React Native Metro报错‘Failed to construct transformer’求助

Hey there, sorry to hear you ran into this frustrating hiccup after tweaking your Android version code/name. The good news is this error almost never ties directly to those version changes—it’s just a timing coincidence. Let’s walk through some tried-and-true fixes to get your Metro server back up and running smoothly:

• Reset Metro’s cache completely
  Corrupted cache is the #1 culprit here. Skip the basic restart and run this command to wipe Metro’s cache entirely:

  npx react-native start --reset-cache
  

  This forces Metro to rebuild all its transformers from scratch, which often resolves the "call retries exceeded" error right away.

• Free up Metro’s default port (8081)
  Sometimes a leftover process or another app is hogging the port Metro uses. Here’s how to kill it:

  • On Windows:

    netstat -ano | findstr :8081
    taskkill /PID <your-process-ID> /F
    

  • On Mac/Linux:

    lsof -ti:8081 | xargs kill -9
    

  After freeing the port, restart Metro with npx react-native start.

• Clean Android build artifacts
  Since you modified Android config files, leftover build cache might be causing unexpected conflicts. Head into your android folder and run:

  • Windows: gradlew clean
  • Mac/Linux: ./gradlew clean
    Then return to your project root and restart your app.

• Check Node.js version compatibility
  The jest-worker error often pops up if your Node.js version clashes with your React Native/Metro setup. Use a version manager like nvm to switch to a stable, recommended version (16.x or 18.x work for most recent RN projects):

  nvm use 18
  rm -rf node_modules yarn.lock
  yarn install
  

• Resolve dependency lock file conflicts
  Mismatched versions of jest-worker in your lock file can cause hidden issues. Back up your yarn.lock or package-lock.json, delete it, then reinstall dependencies fresh:

  rm yarn.lock
  yarn install
  

If none of these work, try deleting the hidden .metro-cache folder in your project root, then restart Metro again. Most folks fix this with the first or second step, so start there!

内容的提问来源于stack exchange，提问作者narutoobito