How to fix "__dirname is not defined in ES module scope"

Problem

I ran into this error when using __dirname in an ES module.

__dirname is an environment variable that tells you the absolute path of the directory containing the currently executing file, and many Node.js projects use this.

But if you use it inside an ES module, you can't use it because of the infamous "__dirname is not defined in ES module scope" an error appears.

Solution

What can you do in this case?

To get the current file directory, we'll want to use a combination of a global variable and a few built-in methods:

• import.meta.url to get the current file as a URL
• url.fileURLToPath to change the URL to a path
• path.dirname to get the directory name

Using these methods, we can reconstruct the global __dirname and __filename variables:

import path from 'path';
import { fileURLToPath } from 'url';

const __filename = fileURLToPath(import.meta.url);

const __dirname = path.dirname(__filename);

Now you can use __dirname as usual:

console.log(__dirname)

Conclusion

Due to the different approaches to modularity in Node.js and EcmaScript, you may encounter such problems.

If you are working with file paths, you may also find it useful to know how to check if a file exists in Node.js.

For further reading, check out the Node.js documentation for __dirname.