Fix: __dirname is not defined in ES module scope (Node 24)

console.log(path.join(__dirname, "data.json"));
                      ^
ReferenceError: __dirname is not defined in ES module scope
This file is being treated as an ES module because it has a '.js' file
extension and 'package.json' contains "type": "module".

The fix

Use import.meta.dirname. It’s built into Node and needs no imports:

import path from "node:path";

const dataFile = path.join(import.meta.dirname, "data.json");
console.log(import.meta.dirname);  // folder of this file
console.log(import.meta.filename); // full path of this file

import.meta.dirname and import.meta.filename were added in Node 20.11. If you’re stuck on an older Node, use the classic two-line fallback:

import path from "node:path";
import { fileURLToPath } from "node:url";

const __filename = fileURLToPath(import.meta.url);
const __dirname = path.dirname(__filename);

Why it happens

__dirname, __filename and require are not real globals. Node injects them into every CommonJS file. ES modules don’t get them, because ESM identifies files by URL (import.meta.url) rather than by path.

Your file is treated as an ES module when either of these is true:

• package.json has "type": "module" and the file ends in .js
• the file ends in .mjs

The error message says which one applies to you.

What didn’t work