Fixing "ReferenceError: module is not defined in ES module scope" When Working With next.config

This blog post will briefly discuss the cause and solution to the error "ReferenceError: module is not defined in ES module scope" when working with /next.config.mjs.

The Solution

To fix this error, simply replace module.exports with export default. This syntax is the correct way to export variables or functions from an ES module.

Here's the corrected code:

export default nextConfig;

Understanding the Error

The error arises from the use of module.exports in an ES module. ES modules have their own scope, and module is not defined within this scope. This means you cannot use module.exports to export variables or functions from an ES module.

In /next.config.mjs, which is typically written in the ES module format, using module.exports will lead to the error "ReferenceError: module is not defined."

This error was caused by:

// module.exports = nextConfig;

Conclusion

By switching to export default, you ensure your /next.config.mjs file is compatible with the ES module syntax and avoids the ReferenceError. This allows you to continue using Next.js features without encountering this error.