Module-relative resources
Load configuration, templates, or other files stored beside a CommonJS module regardless of the launch directory.
Node.js · Pipe
__dirname
__dirname is a CommonJS module-local string containing the directory of the currently executing script. Use it to build paths anchored to that module instead of the process's working directory.
- Since
- v0.1.27
How it works
In a CommonJS module, __dirname is a string containing the directory of the currently executing module. It is scoped to each module rather than being a true global, so dependencies receive paths based on their own locations; combine it with node:path to create module-relative paths.
Syntax
__dirnameReturns
A string containing the directory name of the currently executing script.
Key points
- Node.js introduced
__dirnamein version 0.1.27. - The value identifies the directory containing the currently executing script.
- Its scope is each module, despite the global-style name.
- A dependency resolves
__dirnameaccording to the dependency module's own location.
Common mistakes
- Treat it as module-local context, not as a process-wide global value; code in a dependency gets that dependency's directory.
- It identifies the executing script's directory, not necessarily the directory from which the
nodecommand was launched.
Example: Resolve a module-relative path
console.log(__dirname);
console.log(path.join(__dirname, 'config.json'));Prints the current CommonJS module directory and builds an absolute path to a file located beside that module.
When to use it
Dependency-local paths
Give each package or dependency a path rooted in its own installed module directory.
Interview questions
QWhat does __dirname contain?
__dirname is a CommonJS-provided string containing the directory of the currently executing script. It is local to the module, so each module resolves it relative to its own file.
Follow-up: How would you construct a path to a sibling file? Use path.join(__dirname, 'file.ext'), then pass the result to the relevant filesystem API.
QIs __dirname a true global?
No. The documentation describes it as local to each module rather than an actual global. A dependency therefore sees its own module directory, not the application's directory.
Follow-up: What should code use when it needs the application's working directory? Use process.cwd(), because that represents the process working directory rather than the module location.
QWhy use __dirname instead of a relative path?
It is useful for paths that should remain anchored to the module's location, such as configuration files or assets shipped beside the source file. This avoids depending on the caller's current working directory.
Follow-up: What changes when the same code is packaged as a Node.js single executable application? The official documentation notes that an injected module's __dirname equals the directory name of process.execPath.
Related
__filenamepath.dirname()process.cwd()