Configuration File

nr is configured using a JavaScript configuration file named nr.config.js that should be placed in the root directory of your project.

A configuration file is responsible for creating commands, tasks, and scripts:

• Commands describe the invocation of a single executable and any arguments provided to it, as well as any configuration related to how the command should be invoked and how its output should be handled.

• Tasks are JavaScript functions that may execute arbitrary code. They may be synchronous or asynchronous.

• Scripts are the entry-point to nr. They compose commands, tasks, and other scripts that may run sequentially, in parallel, or a combination of both.

A configuration file must export a function that will be passed a ConfigurationFactoryContext object that contains the following properties:

Key	Type	Description
command	function	Creates a new command.
task	function	Creates a new task.
script	function	Creates a new script.
isCI	boolean	true in CI environments. See is-ci.

These functions are documented in more detail later in this guide.

ESM

The examples in this guide are written in modern ESM syntax. If your project is configured to support this syntax, either by declaring "type": "module" in package.json or via Babel, you can author your nr configuration file the same way.

nr.config.js

export default ({ command, task, script }) => {
  // Define scripts here.
};

Note: If your project uses Babel to provide support for modern language features, nr will automatically use your project's local Babel configuration. You do not need to use a .babel.js extension.

CommonJS

If your project is not configured to support ESM syntax, you will need to author your configuration file using CommonJS syntax:

nr.config.js

module.exports = ({ command, task, script }) => {
  // Define scripts here.
};

Hello World Example

Here, we will define a simple script that runs a single command that outputs "Hello world!". Use this as a sanity check to ensure nr can find and parse your configuration file. The concepts used here will be covered in more detail later in the guide.

nr.config.js

export default ({ command, script }) => {
  script('hello-world', {
    run: [
      command('hello-world', ['echo', ['Hello world!']])
    ]
  });
};

Verify that you can run this script using one of the following commands, depending on how you have configured your environment:

Command Line

$ nr hello-world
Hello world!

Command Line

$ npx nr hello-world
Hello world!

Once you have created your configuration file, proceed to the next section to learn how to create your first script.