A Beginner's Guide
Building a Simple Example App with Express.js:Express.js, a minimalist web framework for Node.js, is widely used for building web applications and APIs due to its simplicity, flexibility, and scalability. In this article, we'll walk through the process of creating a simple example app using Express.js. By following along, you'll gain a solid understanding of how to structure and build applications with Express.js.
Prerequisites
Before we begin, ensure [url=https://telemadata.com/malaysia-phone-numbers/]malaysia phone number[/url] you have Node.js and npm (Node Package Manager) installed on your system. You can download and install them from the official Node.js website if you haven't already.
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Step 1: Setup
Start by creating a new directory for your project and navigating into it:
bash
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mkdir express-example-app
cd express-example-app
Initialize a new Node.js project by running the following command and following the prompts:
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npm init -y
Step 2: Install Express
Next, install Express.js as a dependency for your project:
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npm install express
Step 3: Create Your Express App
Create a new JavaScript file (e.g., app.js) and open it in your preferred code editor. This file will serve as the entry point for your Express app.
javascript
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// Import the Express module
const express = require('express');
// Create an Express application
const app = express();
// Define a route handler for the root path
app.get('/', (req, res) => {
res.send('Hello, Express!');
});
// Start the server
const port = process.env.PORT || 3000;
app.listen(port, () => {
console.log(`Server is running on port ${port}`);
});
In this code:
We import the Express module and create an Express application.
We define a route handler for the root path (/) that responds with "Hello, Express!".
We start the Express server, listening on port 3000 by default.
Step 4: Run Your Express App
To run your Express app, execute the following command in your terminal:
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node app.js
You should see the message "Server is running on port 3000" logged to the console. Your Express app is now running locally on port 3000.
Step 5: Test Your Express App
Open your web browser and navigate to http://localhost:3000. You should see the message "Hello, Express!" displayed in the browser. Congratulations! You've successfully created and tested your first Express app.
Adding More Routes
To add more routes to your Express app, simply define additional route handlers using the app.get, app.post, app.put, app.delete, etc., methods provided by Express.
javascript
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// Define route handler for /about
app.get('/about', (req, res) => {
res.send('About Us');
});
// Define route handler for /contact
app.get('/contact', (req, res) => {
res.send('Contact Us');
});
Conclusion
In this article, we've covered the basics of creating a simple example app with Express.js. We've learned how to set up a new Express project, define routes, and run the Express server. With this foundation, you can continue to explore and build more complex web applications and APIs using Express.js.
Express.js's minimalist approach and powerful features make it an excellent choice for building web applications of all sizes. Whether you're building a small personal project or a large-scale enterprise application, Express.js provides the tools and flexibility you need to get the job done efficiently.
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