by Sai gowtham

Passing the command line arguments to npm script

In this tutorial, we are going to learn about how to pass the command line arguments to an npm script in Node.js.

Consider, we have a following script in our package.json file.

"scripts": {
    "start": "node app.js"
},

To pass the command line arguments to the above npm script, we can use the -- sign followed by the key=value pairs.

npm start --port=3000

Now, we can access the command line arguments inside an app.js file like this:

app.js
const port = process.env.npm_config_port;

console.log(port); // 3000

You can also pass multiple command-line arguments to a npm script like this:

npm start --port=3000 --name=king

Inside app.js file:

app.js
const port = process.env.npm_config_port;
const name = process.env.npm_config_name;

console.log(port);  // 3000
console.log(name); // "king"

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