Dirname Does Not Follow Symlink

Node’s global object __dirname returns the name of the directory that the currently executing script resides in. However, if a directory is symbolic linked or a symlink, it still return the original path.

For example, the following directory structure:

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/tmp/dirname/
├── foo
│   └── app.js
└── lib
    ├── bar -> ../foo
    └── util.js
3 directories, 2 files

The app.js contains the following line:

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console.log(__dirname);

Run the script:

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$ cd /tmp/dirname/foo && node app.js
/tmp/dirname/foo

You get the directory the app.js script is residing it. But if you do the same from the symlinked directory:

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$ cd /tmp/dirname/lib/bar && node app.js
/tmp/dirname/foo

Well, you get the same answer, even the current working directory is different:

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$ cd /tmp/dirname/lib/bar && pwd
/tmp/dirname/lib/bar

The return of __dirname does not follow symbolic link.

So, have to be extra careful when requiring files that is symbolic linked. If you think you are in lib/bar directory and try to require the util.js script in app.js:

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var path = require('path');
console.log(require('../util'));
console.log(require(path.join(__dirname, '..', 'util')));

Both statements will throw module not found error. Path join does not help either.

The best practice is to avoid symlinks and relative directory requiring. Instead, set up required as modules, and install them in node_modules directory, then they will become top-level modules.