Node.js Basics

Node.js Basics

In this guide, we’ll provide an overview of Node.js, including how to set up a Node.js environment, work with modules, and use npm (Node Package Manager).

What is Node.js?

Node.js is an open-source, cross-platform JavaScript runtime environment that allows you to run JavaScript code on the server-side. It uses the V8 JavaScript engine from Google Chrome to execute code outside the browser.

Setting up a Node.js Environment

1. Installation: Visit the official Node.js website and download the installer for your operating system. Follow the installation instructions provided.

2. Checking Installation: Open a terminal or command prompt and run the following command to verify that Node.js and npm are installed:

    node -v
    npm -v
   

   This will display the installed Node.js version and npm version.

Working with Modules

Node.js uses a module system to organize code into reusable components. Each file in Node.js is treated as a module. You can create your own modules and import built-in or third-party modules using the require function.

1. Creating a Module: Create a new JavaScript file (e.g., myModule.js) and define a function or variable:

    // myModule.js
    const greeting = "Hello, ";
   
    function greet(name) {
        console.log(greeting + name);
    }
   
    module.exports = greet;
   

2. Using a Module: In another file, use the require function to import the module and access its functionality:

    // main.js
    const myModule = require('./myModule');
   
    myModule('John');
   

Using npm (Node Package Manager)

npm is the default package manager for Node.js, allowing you to install, manage, and share JavaScript packages and libraries.

1. Initializing a Project: Navigate to your project directory in the terminal and run the following command to create a package.json file:

    npm init
   

   Follow the prompts to set up your project details.

2. Installing Packages: Use the npm install command to install packages locally. For example, to install the Express.js framework:

    npm install express
   

3. Using Installed Packages: After installing a package, you can require it in your code just like any other module:

    const express = require('express');
   

4. Managing Dependencies: Update dependencies listed in package.json by running:

    npm update
   

   This will update packages to their latest versions based on the version constraints specified in package.json.

Node.js, with its module system and npm, provides a powerful platform for building scalable and efficient server-side applications using JavaScript.