Running a Node.js Script: A Step-by-Step Tutorial

In this tutorial, we will learn how to create and run a Node.js script. Node.js is a powerful JavaScript runtime that allows you to run JavaScript code on the server-side. It is widely used for building web applications, APIs, and other server-side applications.

To get started with Node.js, you will need to have Node.js installed on your computer. You can download and install Node.js from the official website (https://nodejs.org/). Once you have Node.js installed, you can check the version by opening a terminal or command prompt and running the following command:

node -v

This will display the version of Node.js installed on your computer.

Now, let’s create our first Node.js script. Create a new file with a .js extension, for example, script.js. Open the file in a text editor or an IDE of your choice.

In the file, you can write your JavaScript code. For example, let’s create a simple script that prints "Hello, World!" to the console:

console.log("Hello, World!");

Save the file.

To run the Node.js script, open a terminal or command prompt and navigate to the directory where the script is saved. Then, run the following command:

node script.js

This command tells Node.js to run the script.js file. You should see the output "Hello, World!" printed to the console.

You can also run JavaScript code directly in the Node.js REPL (Read-Eval-Print Loop). To open the Node.js REPL, run the following command in the terminal or command prompt:

node

This will open the Node.js REPL, where you can type JavaScript code and see the results immediately. For example, you can type:

console.log("Hello, World!");

and press Enter to see the output "Hello, World!" printed to the console.

In addition to running scripts and code in the Node.js REPL, you can also install and use npm packages in your Node.js scripts. npm is the package manager for Node.js and it allows you to easily install and manage dependencies for your projects.

To install a npm package, run the following command in the terminal or command prompt:

npm install package-name

This will install the specified npm package and its dependencies in the current project directory. You can then require the package in your Node.js script using the require function.

For example, to use the popular lodash library, you can install it with the following command:

npm install lodash

Then, you can require lodash in your script.js file:

const _ = require('lodash');

console.log(_.upperCase('hello, world!'));

Save the file and run it with the node script.js command. You should see the output "HELLO, WORLD!" printed to the console.

In this tutorial, we learned how to create and run a Node.js script, use the Node.js REPL, and install npm packages. Node.js is a powerful tool for building server-side applications and it provides a lot of flexibility and functionality for JavaScript developers. Experiment with different scripts and npm packages to explore the capabilities of Node.js further.

I hope this tutorial was helpful in getting you started with Node.js. Happy coding!