React App Build Failure on Vercel: "react-scripts build" Exited with 127 - A Comprehensive Guide
The Problem: You're trying to deploy your React app to Vercel, but the build process fails with the cryptic error "react-scripts build exited with 127". This can be incredibly frustrating, especially when you're confident your code works locally.
Understanding the Error: This error essentially means that the command "react-scripts build" could not be found or executed successfully. It's like trying to start your car, but the key isn't turning the ignition.
Scenario and Code Example:
Imagine you have a simple React app with a package.json file containing the following:
{
"name": "my-react-app",
"version": "1.0.0",
"main": "src/index.js",
"scripts": {
"start": "react-scripts start",
"build": "react-scripts build"
},
"dependencies": {
"react": "^18.2.0",
"react-dom": "^18.2.0",
"react-scripts": "^5.0.1"
}
}
You push your code to Vercel and the build process fails, showing the error "react-scripts build exited with 127".
Common Causes & Solutions:
-
Missing or Incorrect Dependencies: The most likely culprit is a missing or outdated "react-scripts" package. Double-check that your
package.jsonhas the correct version ofreact-scriptsand that it's installed locally. You can runnpm install react-scriptsoryarn add react-scriptsto install or update it. -
Misconfigured Build Script: Ensure your
package.jsonhas the correct build script:"build": "react-scripts build". Sometimes a typo or accidental change can cause problems. -
Missing Node.js on Vercel: Vercel needs Node.js to run the build process. If Node.js isn't installed on your Vercel project, the build will fail. You can verify this by checking the "Environment" section of your project settings in Vercel. If Node.js isn't listed, you'll need to add it.
-
Conflicting Packages: Occasionally, a conflicting package from your dependencies might interfere with "react-scripts". Try temporarily removing non-essential packages and re-running the build to isolate the problem.
Additional Tips:
- Clear Cache: If you've made changes to your
package.json, try clearing your local node_modules directory (rm -rf node_modules) and reinstalling dependencies (npm install). - Update "react-scripts": Regularly update your
react-scriptspackage to benefit from bug fixes and performance improvements. - Check Vercel Logs: Examine the Vercel logs for more detailed information about the error. This can provide specific clues about the cause of the problem.
- Test Locally: Make sure your build works locally before deploying to Vercel. This helps eliminate potential issues related to your local environment.
Resources:
By understanding the common causes of the "react-scripts build exited with 127" error and implementing the solutions described above, you'll be well-equipped to debug and resolve this issue, enabling you to smoothly deploy your React apps to Vercel.
