Running into “Cannot read properties of undefined (reading ‘prototype’)” in the Process of upgrading from react-scripts 4 > 5?

Are you stumped by this pesky error while upgrading from react-scripts 4 to 5? Fear not, dear developer! This article is here to guide you through the troubleshooting process, providing clear and direct instructions to help you overcome this hurdle.

What’s causing the error?

The error “Cannot read properties of undefined (reading ‘prototype’)” typically occurs when there’s an issue with the way you’re accessing or using a property in your React application. In the context of upgrading from react-scripts 4 to 5, this error can be attributed to several factors, including:

• Incompatible third-party libraries or dependencies
• Changes in the React scripts configuration
• Incorrect or outdated setup for Webpack or Babel
• Conflicting or duplicate dependencies

Step 1: Identify the Culprit

To begin troubleshooting, you need to identify which part of your application is causing the error. Follow these steps:

1. Check the error message: Take a closer look at the error message and try to identify the specific file, component, or function that’s causing the issue.
2. Review your code changes: Think back to the changes you made during the upgrade process and pinpoint any recent modifications that might be related to the error.
3. Use the React DevTools: Utilize the React DevTools to inspect the component tree and identify which component is throwing the error.

Step 2: Update Dependencies and Configuration

It’s essential to ensure that all dependencies, including third-party libraries, are compatible with react-scripts 5. Follow these steps:

Update dependencies:

  npm install react-scripts@5
  npm install @babel/[email protected]
  npm install [email protected]
  npm install [email protected]

Update your babel.config.js file:

  
    module.exports = {
      presets: ['react-app'],
    };
  

Update your webpack.config.js file (if you have one):

  
    module.exports = {
      // ... other configurations ...
      module: {
        rules: [
          {
            test: /\.(js|mjs|jsx|ts|tsx)$/,
            include: paths.appSrc,
            loader: require.resolve('babel-loader'),
            options: {
              customize: require.resolve(
                'babel-preset-react-app/webpack-overrides'
              ),
              plugins: ['react-refresh/babel'],
            },
          },
        ],
      },
    };
  

Step 3: Verify Webpack and Babel Setup

To ensure that Webpack and Babel are set up correctly, follow these steps:

Check your webpack.config.js file:

  
    module.exports = {
      // ... other configurations ...
      module: {
        rules: [
          {
            test: /\.(js|mjs|jsx|ts|tsx)$/,
            include: paths.appSrc,
            loader: require.resolve('babel-loader'),
            options: {
              customize: require.resolve(
                'babel-preset-react-app/webpack-overrides'
              ),
              plugins: ['react-refresh/babel'],
            },
          },
        ],
      },
    };
  

Verify that you have the correct version of Webpack and Babel installed:

  
    npm ls webpack
    npm ls @babel/core
  

Step 4: Resolve Conflicting Dependencies

Conflicting dependencies can cause issues during the upgrade process. To resolve this, follow these steps:

Check for duplicate dependencies:

  
    npm ls
  

Remove duplicate dependencies:

  
    npm uninstall 
  

Check for incompatible dependencies:

  
    npm ls 
  

Update incompatible dependencies to a compatible version:

  
    npm install @compatible-version
  

Troubleshooting Tips and Tricks

Here are some additional tips to help you troubleshoot the error:

• Clear your node_modules folder and run npm install again.
• Try resetting your React project by running npx react-scripts reset.
• Check your package.json file for any incorrect or outdated dependencies.
• Search for similar issues on GitHub or Stack Overflow to find potential solutions.

Conclusion

Upgrading from react-scripts 4 to 5 can be a complex process, and errors like “Cannot read properties of undefined (reading ‘prototype’)” can be frustrating. However, by following the steps outlined in this article, you should be able to identify and resolve the issue. Remember to stay calm, be patient, and don’t hesitate to seek help from the React community.

Error	Cause	Solution
“Cannot read properties of undefined (reading ‘prototype’)”()	Incompatible dependencies, changes in React scripts configuration, incorrect Webpack or Babel setup, or conflicting dependencies	Update dependencies, verify Webpack and Babel setup, resolve conflicting dependencies, and troubleshoot using React DevTools

I hope this article has been helpful in guiding you through the troubleshooting process. If you have any further questions or need additional assistance, feel free to ask in the comments below.

Frequently Asked Question

Stuck in the middle of upgrading from react-scripts 4 to 5 and encountering the dreaded “Cannot read properties of undefined (reading ‘prototype’)” error? Worry not, friend! We’ve got the answers to get you back on track.