✋ Update: This post was originally published on my blog decodingweb.dev, where you can read the latest version for a 💯 user experience. ~reza
The error "__dirname
is not defined in ES module scope" means you're using __dirname
global variable in an ES (ECMAScript) module.
Here’s what the error look like:
file:///dwd/sandbox/utils.js:2
return __dirname
^
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 '/home/dwd/sandbox/package.json' contains type: module. To treat it as a CommonJS script, rename it to use the '.cjs' file extension.
What does __dirname
mean in Node? You may ask.
The __dirname
global variable contains the path to the current module's directory.
The global variables __dirname
and __filename
only exist in CommonJS modules and aren't available in ES modules.
So if you've enabled ES modules in Node.js (via "type": "module"
in package.json
) or using ES modules through a module bundler like Webpack, you'll no longer have access to these global variables.
This error is one of the most common errors developers face when switching from CommonJS modules to ES modules.
The workaround is quite easy, though. Here's how it's done:
- Get the module file URL from the
import.meta
object - Convert the URL to a path by
fileUrlToPath()
- Get the module's directory by using the
path.dirname()
method
import { fileURLToPath } from 'url';
import path from 'path';
const __filename = fileURLToPath(import.meta.url);
const __dirname = dirname(__filename);
The import.meta
object exposes context-specific metadata to a JavaScript module, including the module's URL.
Whenever you need the __dirname
value, you'll have to repeat the above instructions. It's better to create a helper function.
Create a helper function to emulate __dirname functionality
You can create a helper function, which you can call anytime you need the __dirname
value.
// utils.js
import path from 'path'
import { fileURLToPath } from 'url'
const getDirName = function (moduleUrl) {
const filename = fileURLToPath(moduleUrl)
return path.dirname(filename)
}
export {
getDirName
}
And use it like so:
// ModuleA.js
import { getDirName } from './libs/utils'
// Getting the dirname of moduleA.js
const dirName = getDirName(import.meta.url)
console.log(dirName)
// output: /home/dwd/sandbox/modules
Please note you'll have to provide the import.meta.url
when calling the getDirName
function; If you refer to it from inside the lib.js
module, it'll return the utils.js
directory name (/home/dwd/sandbox/libs
).
I hope this guide was helpful.
Thanks for reading.
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Top comments (1)
Great article, you got my follow, keep writing!