README.md

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In the previous lessons, we learned about the package.json and its usage in creating Node.js applications. We will learn more about the inbuilt features in package.json to make our development easier.

npm scripts property

The scripts property of your package.json supports many built-in scripts. These all can be executed by running npm run <stage> for short.

The <stage> above refers to the pre-built stages available for package.json which we can configure or custom ones that we can create and execute using npm.

You can refer to the npm scripts reference document for mode details on the options available to use with this property.

Running your first Node.js program using npm

In the previous levels, you might have already created your first Node.js program. While running the same, you might have used the below command.

node index.js

While this is the right way to run the Node.js code, when you have a huge application with many dependencies which need to be combined before execution this will become tedious.

Using npm scripts, we can solve this issue.

Navigate to the package.json in your Node.js application folder.

Update the following to the scripts attribute along with the test attribute.

"start": "node index.js"

The final package.json will look something like the one below.

{
"name": "hello-node",
"version": "1.0.0",
"description": "",
"main": "index.js",
"scripts": {
  "start": "node index.js",
  "test": "echo \"Error: no test specified\" && exit 1"
},
"author": "",
"license": "ISC"
}

Now to execute the Node.js program, all you have to do is to navigate to the folder of the application and execute the following command in Terminal.

npm run start

You can notice that the above command internally executes the node index.js command and the result is displayed in the Terminal.

You can also use the above command without the run keyword, as the start function is added by default in the package.json.

npm start

The above execution also returns a similar result.

You can also add custom scripts based on your project requirements. We will learn more about these while working on the future levels.