Resolving the TypeError: Class extends value undefined is not a constructor or null in Next.js

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This error can suddenly appear when you run your development server using the command npm run dev, leaving you puzzled about its source and solution.

Understanding the Error

Common Causes

Here are some potential causes for this error:

Dependency Conflicts: Your project may have conflicting versions of packages.

Corrupt Installation: Sometimes, files in the node_modules directory can become corrupted.

Cache Issues: The npm cache may contain outdated information that could be causing the problem.

Improper Imports: Errors in how modules are imported can lead to similar issues.

Steps to Resolve the Error

Fortunately, there are straightforward solutions to tackle this issue. Let's break them down into easy-to-follow steps:

Step 1: Clear the node_modules Directory

The first step to resolving this error is often to remove the node_modules directory and reinstall your dependencies. Here’s how you can do it:

Run the following commands in your terminal:

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Step 2: Clear npm Cache (Optional)

In some cases, it may be beneficial to also clear the npm cache to ensure that old or corrupt files are removed. To do this, run:

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This step cleans the npm cache, potentially fixing issues caused by corrupt cache files.

Step 3: Verify Dependency Versions

Step 4: Re-run Your Application

Finally, try running your application again:

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If your setup was restored correctly, the error should be resolved and your application should run smoothly.

Conclusion