Sending Command Line Arguments to Npm Script

Sending Command Line Arguments to npm Script

When working with JavaScript projects, you might often find yourself needing to pass command line arguments to npm scripts. Whether it’s for configuring different environments, specifying build options, or any other use case, being able to send command line arguments to npm scripts can be incredibly useful. In this article, we will explore different ways to achieve this.

Method 1: Using process.argv

One way to send command line arguments to an npm script is by using the process.argv property. process.argv is an array that contains the command line arguments passed to the Node.js process. The first two elements of the array are always the path to the Node.js executable and the path to the script being executed. The subsequent elements are the command line arguments.

Here’s an example of how you can access the command line arguments in an npm script:

"scripts": {
  "my-script": "node script.js"
}

In the above example, if you run npm run my-script arg1 arg2, the command line arguments arg1 and arg2 can be accessed in the script.js file as follows:

const args = process.argv.slice(2);
console.log(args); // Output: ['arg1', 'arg2']

You can then use the args array in your script to perform any necessary actions based on the command line arguments.

Method 2: Using npm-run-all

If you prefer a more flexible approach, you can use a package like npm-run-all to send command line arguments to npm scripts. npm-run-all allows you to define complex run scripts and pass arguments to them.

First, install npm-run-all as a development dependency:

npm install --save-dev npm-run-all

Next, define your npm script using the npm-run-all command:

"scripts": {
  "my-script": "run-s my-task --arg1=value1 --arg2=value2",
  "my-task": "node script.js"
}

In the above example, the my-script script runs the my-task script with the specified command line arguments.

In your script.js file, you can access the command line arguments using the process.argv property, as shown in Method 1.

Using npm-run-all gives you more control over how the command line arguments are passed to your scripts, allowing you to define complex argument structures.

Conclusion

Sending command line arguments to npm scripts can be achieved using the process.argv property or by using a package like npm-run-all. Both methods provide a way to pass arguments to your scripts and enable you to customize the behavior of your npm scripts based on the provided arguments.

Remember to choose the method that best suits your needs and project requirements. Happy coding!

Sending Command Line Arguments to Npm Script