app-root-path

What is app-root-path?

The app-root-path package is designed to allow Node.js applications to easily determine their root directory. This is particularly useful in scenarios where the application's structure is complex or when it is deployed in an environment where the current working directory is not consistent. The package provides a straightforward API to obtain the root path of the application, making it easier to reference files and directories relative to the application's root.

What are app-root-path's main functionalities?

Determine application root path

This feature allows you to determine the root path of your application. By calling `toString()` on the `appRoot` object, you can get the absolute path to the root directory of your application. This is useful for constructing paths to other resources in your application.

const appRoot = require('app-root-path');
console.log(appRoot.toString());

Resolve paths relative to application root

This feature enables you to resolve paths relative to the application's root directory. By using the `resolve` method, you can easily construct absolute paths to any file or directory within your application, without worrying about the current working directory.

const appRoot = require('app-root-path');
const pathToSomeFile = appRoot.resolve('/path/to/some/file');
console.log(pathToSomeFile);

Require modules relative to application root

This feature simplifies requiring modules that are located relative to the application's root directory. Instead of using complex relative paths, you can use `appRoot.require` to directly require modules based on their path relative to the application's root. This can make code more readable and maintainable.

const appRoot = require('app-root-path');
const myModule = appRoot.require('/path/to/module');

Other packages similar to app-root-path

find-root

The find-root package provides functionality to find the root directory of a Node.js project by looking for a 'package.json' file. Unlike app-root-path, which determines the application root based on the main module's location, find-root works by traversing up the directory tree until it finds a 'package.json' file. This approach may yield different results in certain project structures.

pkg-dir

pkg-dir is another package that helps in finding the root directory of a Node.js project. Similar to find-root, it works by searching for a 'package.json' file in the current directory or any parent directory. pkg-dir returns a promise, making it suitable for use in asynchronous operations. It provides a similar functionality to app-root-path but with a promise-based API.

README

App Root Path Module

Please Note: Due to the very limited scope of this module, I do not anticipate needing to make very many changes to it. Expect long stretches of zero updates—that does not mean that the module is outdated.

This simple module helps you access your application's root path from anywhere in the application without resorting to relative paths like require("../../path").

Installation

$ npm i -S app-root-path

Usage

To simply access the app's root path, use the module as though it were a string:

var appRoot = require('app-root-path');
var myModule = require(appRoot + '/lib/my-module.js');

Side note: the module actually returns an object, but that object implements the toString method, so you can use it as though it were a string. There are a few edge cases where this might not be the case (most notably console.log), but they shouldn't affect actual use of the module, where you're almost always concatenating with an additional string.

A helper function is also provided:

var reqlib = require('app-root-path').require;
var myModule = reqlib('/lib/my-module.js');

It's a little hacky, but you can also put this method on your application's global object to use it everywhere in your project:

// In app.js
global.reqlib = require('app-root-path').require;

// In lib/module/component/subcomponent.js
var myModule = reqlib('/lib/my-module.js');

Finally, you can also just resolve a module path:

var myModulePath = require('app-root-path').resolve('/lib/my-module.js');

You can explicitly set the path, using the environmental variable APP_ROOT_PATH or by calling require('app-root-path').setPath('/my/app/is/here')

How It Works (under the hood)

No need to read this unless your curious—or you run into a (very unlikely) case where the module does not work as expected.

This module uses two different methods to determine the app's root path, depending on the circumstances.

Primary Method

If the module is located inside your project's directory, somewhere within the node_modules directory (whether directly, or inside a submodule), we effectively do (the actual code takes cross-platform path names/etc into consideration):

path.resolve(__dirname).split('/node_modules')[0];

This will take a path like /var/www/node_modules/submodule/node_modules/app-root-path and return /var/www. In nearly all cases, this is just what you need.

Secondary Method (for edge cases)

The node module loader will also look in a few other places for modules (for example, ones that you install globally with npm install -g). These can be in one of:

• $HOME/.node_modules
• $HOME/.node_libraries
• $PREFIX/lib/node

Or, anywhere in the NODE_PATH environmental variable (see documentation).

In these cases, we fall back to an alternate trick:

path.dirname(require.main.filename);

When a file is run directly from Node, require.main is set to that file's module. Each module has a filename property that refers to the filename of that module, so by fetching the directory name for that file, we at least get the directory of file passed to node. In some cases (process managers and test suites, for example) this doesn't actually give the correct directory, though, so this method is only used as a fallback.

Edge-Case: Global CLIs

If your module is installed as a global CLI, for example in /usr/local/lib/node_modules/yourmodule, then require.main.filename will report /usr/local/lib/node_modules/yourmodule/bin, which is probably not what you want. app-root-path is aware of this edge-case and will strip the /bin automatically.

Change Log

1.3.0

• Updated electron to match changes in version 1.0 of that project

1.2.1

• Had to bump package version because 1.2.0 got published to npm as @beta

1.2.0

• Special logic to resolve correctly when in an electron renderer process

1.1.0

• Special logic to handle an edge case when used in a globally-installed CLI project
• Fixed a bug where setPath() did not update require('app-root-path').path
• Moved some logic outside of the resolve() function so that it's not called multiple times

1.0.0

• No changes. Just updated the version to signify a locked API (see semver).

0.1.1

• Added Windows support (and, theoretically, other operating systems that have a directory separator that's not "/")

0.1.0

• Completely rewrote the path resolution method to account for most possible scenarios. This shouldn't cause and backwards compatibility issues, but always test your code.
• Removed the need to pass a modules's require() method to the appRootPath.require() function. Which it's true that each module has its own require() method, in practice it doesn't matter, and it's much simpler this way.
• Added tests