Node.js Get Started

Last modified on: October 19, 2024

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<h3>Node.js Get Started: A Beginner's Guide to Building with Node.js</h3>
<p>This guide will walk you through setting up Node.js, writing your first program, and understanding the basics of building a server using Node.js. It is designed for developers new to Node.js who want to get started with server-side JavaScript development.</p>
<hr />
<h3>What is Node.js?</h3>
<p><strong>Node.js</strong> is an open-source, cross-platform runtime environment that allows you to run JavaScript on the server. It&rsquo;s built on Chrome's V8 JavaScript engine and is well-known for its event-driven, non-blocking I/O model, which makes it highly efficient and ideal for building fast, scalable applications, particularly real-time web applications like chat systems, APIs, and more.</p>
<hr />
<h3>Step 1: Install Node.js</h3>
<p>To start working with Node.js, the first step is to install it on your machine.</p>
<h4>1. <strong>Download Node.js</strong></h4>
<ul>
<li>Visit the <a target="_new" rel="noopener">official Node.js website</a>.</li>
<li>Download the latest <strong>LTS (Long-Term Support)</strong> version, which is recommended for most users.</li>
</ul>
<h4>2. <strong>Install Node.js</strong></h4>
<ul>
<li>Follow the installer prompts for your operating system (Windows, macOS, or Linux).</li>
<li>During the installation, Node.js automatically installs <strong>NPM</strong> (Node Package Manager), which is used to manage packages and libraries.</li>
</ul>
<h4>3. <strong>Verify Installation</strong></h4>
<p>Once Node.js is installed, verify that it is working correctly by opening a terminal or command prompt and running the following commands:</p>
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<pre class="language-javascript"><code>node -v   # Check Node.js version
npm -v    # Check NPM version</code></pre>
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<h3>Step 2: Write Your First Node.js Program</h3>
<p>Now that Node.js is installed, let's write a simple program.</p>
<h4>1. <strong>Create a Project Folder</strong></h4>
<p>Create a new directory for your project and navigate into it:</p>
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<pre class="language-javascript"><code>mkdir my-first-node-app
cd my-first-node-app</code></pre>
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<h4>2. <strong>Create a Simple JavaScript File</strong></h4>
<p>Inside your project folder, create a file named <code>app.js</code> and write the following code:</p>
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<pre class="language-javascript"><code>console.log('Hello, Node.js!');</code></pre>
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<h4>3. <strong>Run Your Program</strong></h4>
<p>To run the <code>app.js</code> file, execute the following command in your terminal:</p>
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<pre class="language-javascript"><code>node app.js</code></pre>
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<p>You should see the output:</p>
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<pre class="language-javascript"><code>Hello, Node.js!</code></pre>
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<p>Congratulations, you've just written your first Node.js program!</p>
<hr />
<h3>Step 3: Creating a Simple HTTP Server</h3>
<p>One of the most common uses of Node.js is to build web servers. Here's how to create a simple HTTP server that responds to requests.</p>
<h4>1. <strong>Set Up the Project</strong></h4>
<p>In the same project folder, update the <code>app.js</code> file with the following code to create an HTTP server:</p>
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<pre class="language-javascript"><code>const http = require('http');

// Create an HTTP server
const server = http.createServer((req, res) =&gt; {
    res.writeHead(200, { 'Content-Type': 'text/plain' });
    res.end('Hello, World from Node.js!');
});

// The server listens on port 3000
server.listen(3000, () =&gt; {
    console.log('Server running at http://localhost:3000/');
});</code></pre>
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<h4>2. <strong>Run the HTTP Server</strong></h4>
<p>Run the server by executing:</p>
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<pre class="language-javascript"><code>node app.js</code></pre>
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<p>You&rsquo;ll see the message in the terminal:</p>
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<pre class="language-javascript"><code>Server running at http://localhost:3000/</code></pre>
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<h4>3. <strong>Test the Server</strong></h4>
<p>Open your web browser and go to <code>http://localhost:3000/</code>. You should see the message:</p>
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<pre class="language-javascript"><code>Hello, World from Node.js!</code></pre>
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<p>This simple server listens for incoming HTTP requests on port 3000 and responds with "Hello, World from Node.js!" each time the URL is accessed.</p>
<hr />
<h3>Step 4: Using NPM (Node Package Manager)</h3>
<p>Node.js comes with NPM, a package manager that allows you to install and manage third-party libraries and tools to extend the functionality of your application.</p>
<h4>1. <strong>Initialize the Project</strong></h4>
<p>Initialize your project to create a <code>package.json</code> file, which keeps track of your project&rsquo;s metadata and dependencies:</p>
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<pre class="language-javascript"><code>npm init -y</code></pre>
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<p>This will create a <code>package.json</code> file with default values. You can manually edit this file later if needed.</p>
<h4>2. <strong>Install a Package</strong></h4>
<p>To add a package, use the <code>npm install</code> command. Let&rsquo;s install <strong>Express</strong>, a popular web framework for Node.js:</p>
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<pre class="language-javascript"><code>npm install express</code></pre>
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<p>This command installs Express and creates a <code>node_modules</code> folder, which holds all the project dependencies.</p>
<h4>3. <strong>Use Express in Your Application</strong></h4>
<p>Update the <code>app.js</code> file to use Express and serve a simple response:</p>
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<pre class="language-javascript"><code>const express = require('express');
const app = express();

// Define a route
app.get('/', (req, res) =&gt; {
    res.send('Hello from Express!');
});

// Start the server
app.listen(3000, () =&gt; {
    console.log('Express server running at http://localhost:3000/');
});</code></pre>
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<p>Now, run the server again:</p>
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<pre class="language-javascript"><code>node app.js</code></pre>
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<p>Visit <code>http://localhost:3000/</code> in your browser, and you'll see the message:</p>
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<pre class="language-javascript"><code>Hello from Express!</code></pre>
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<p>You&rsquo;ve now created a server using Express, which simplifies routing and handling requests compared to the native Node.js HTTP module.</p>
<hr />
<h3>Step 5: Managing Dependencies and Scripts</h3>
<h4>1. <strong>Add Dependencies to <code>package.json</code></strong></h4>
<p>When you install packages using NPM, they are automatically added as dependencies in the <code>package.json</code> file. This allows others to install your project&rsquo;s dependencies by simply running:</p>
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<pre class="language-javascript"><code>npm install</code></pre>
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<h4>2. <strong>Add Custom Scripts</strong></h4>
<p>In the <code>package.json</code> file, you can define custom NPM scripts to automate tasks. For example, to start your server with the command <code>npm start</code>, update the <code>scripts</code> section:</p>
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<pre class="language-javascript"><code>"scripts": {
  "start": "node app.js"
}</code></pre>
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<p>Now you can start your application with:</p>
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<pre class="language-javascript"><code>npm start</code></pre>
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<h3>Step 6: Understanding Node.js Modules</h3>
<p>Node.js applications are built around modules, which are reusable pieces of code that encapsulate related functionality. There are two types of modules in Node.js:</p>
<ol>
<li>
<p><strong>Core Modules</strong>: Node.js comes with several built-in modules such as <code>fs</code> (file system), <code>http</code>, <code>url</code>, and <code>path</code>.</p>
</li>
<li>
<p><strong>Custom Modules</strong>: You can create your own modules and export their functionality to other parts of your application.</p>
</li>
</ol>
<h4>Example of Using a Core Module (<code>fs</code>):</h4>
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<pre class="language-javascript"><code>const fs = require('fs');

// Read the content of a file asynchronously
fs.readFile('example.txt', 'utf8', (err, data) =&gt; {
    if (err) throw err;
    console.log(data);
});</code></pre>
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<p>In this example, the <code>fs.readFile()</code> function is used to read the contents of a file asynchronously.</p>
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<h3>Step 7: Conclusion</h3>
<p>You&rsquo;ve just learned the basics of getting started with Node.js! In this tutorial, you installed Node.js, created your first program, set up an HTTP server, used NPM to manage packages, and explored some core modules.</p>
<p>Node.js is a powerful tool for building fast and scalable server-side applications, and by mastering it, you&rsquo;ll be able to build anything from simple APIs to complex real-time applications.</p>
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