Express.js Tutorial

Express.js is a fast, flexible and minimalist web framework for Node.js. It’s effectively a tool that simplifies building web applications and APIs using JavaScript on the server side. Express is an open-source that is developed and maintained by the Node.js foundation.

Express.js offers a robust set of features that enhance your productivity and streamline your web application. It makes it easier to organize your application’s functionality with middleware and routing. It adds helpful utilities to Node HTTP objects and facilitates the rendering of dynamic HTTP objects.

Why learn Express?

Express is a user-friendly framework that simplifies the development process of Node applications. It uses JavaScript as a programming language and provides an efficient way to build web applications and APIs. With Express, you can easily handle routes, requests, and responses, which makes the process of creating robust and scalable applications much easier.

Moreover, it is a lightweight and flexible framework that is easy to learn and comes loaded with middleware options. Whether you are a beginner or an experienced developer, Express is a great choice for building your application.

Express Key Features

1. Middleware and Routing: Express.js makes it easy to organize your application’s functionality using middleware and routing. Middleware functions allow you to handle tasks like authentication, logging, and error handling. Routing ensures that incoming requests are directed to the appropriate handlers.
   
2. Minimalistic Design: Express.js follows a simple and minimalistic design philosophy. This simplicity allows you to quickly set up a server, define routes, and handle HTTP requests efficiently. It’s an excellent choice for building web applications without unnecessary complexity.
   
3. Flexibility and Customization: Express.js doesn’t impose a strict application architecture. You can structure your code according to your preferences. Whether you’re building a RESTful API or a full-fledged web app, Express.js adapts to your needs.
   
4. Scalability: Designed to be lightweight and scalable, Express.js handles a large number of requests asynchronously. Its event-driven architecture ensures responsiveness even under heavy loads.
   
5. Active Community Support: With a thriving community, Express.js receives regular updates and improvements. You’ll find ample documentation, tutorials, and plugins to enhance your development experience.

Getting Started Express

1. Installation: Install Express using npm:

npm install express

2. Basic Example of an Express App:

Node

const express = require('express');
const app = express();

// Define routes and middleware here
// ...

const PORT = process.env.PORT || 3000;
app.listen(PORT, () => {
    console.log(`Server running on port ${PORT}`);
});

Explanation:

1. Import the ‘express’ module to create a web application using Node.js.
2. Initialize an Express app using const app = express();.
3. Add routes (endpoints) and middleware functions to handle requests and perform tasks like authentication or logging.
4. Specify a port (defaulting to 3000) for the server to listen on.

Express Basic:

• Introduction to Express
• Steps to create Express Application
• Design first Application using Express
• How to Structure my Application in Express JS 
• Unique features of Express
• How to send response from server to client using Node and Express ?
• Why Express ‘app’ and ‘server’ files kept separately ?
• How to implement JWT authentication in Express app
• How to expire session after 1 min of inactivity in express-session of Express JS
• Express Error Handling

Express Functions:

Express express():

• Expresson() Function
• express.raw() Function
• express.Router() Function
• express.static() Function
• express.text() Function
• express.urlencoded() Function
• express() function Complete Reference

Express Applications Function:

• app.locals Property
• app.mountpath Property
• Mount Event
• app.all() Function
• app.delete() Function
• app.disable() Function
• app.disabled() Function
• app.enable() Function
• app.enabled() Function
• Application Complete Reference

Express Requests Function:

• req.app Property
• req.baseUrl Property
• req.body Property
• req.cookies Property
• req.fresh Property
• req.accepts() Function
• req.acceptsCharsets() Function
• req.acceptsEncodings() Function
• req.acceptsLanguages() Function
• Request Complete Reference

Express Response Function:

• res.app Property
• res.headersSent Property
• res.locals Property
• res.append() Function
• res.attachment() Function
• res.cookie() Function
• res.clearCookie() Function
• res.download() Function
• res.end() Function
• Response Complete Reference

Express Router Function:

• router.all() Function
• router.METHOD() Function
• router.param() function
• router.route() Function
• router.use() Function
• Router Complete Reference

Express Advanced Topics:

• Node vs Express
• Middlewares in Express
• How to update record in Cassandra using Express 
• What is the use of next() function in Express JS
• How to create custom middleware in express
• Why Express is used in Web Development
• What is Express Generator
• Express HTTP methods
• How to create routes using Express and Postman?
• Why Express Is Used For Enterprise App Development
• REST API using the Express to perform CRUD
• What is express-session middleware in Express

Advanced Concepts

1. Template Engines: Use template engines like EJS or Pug for dynamic content rendering.
2. Error Handling: Implement custom error handling middleware to gracefully handle exceptions.
3. Authentication: Integrate authentication middleware (e.g., Passport.js) for secure user sessions.

More on Express:

• If you are preparing for the interviews, please read the Top 50 Express JS Interview Questions and Answers
• For more article, read the recently published article’s on Express: Recent Articles on Express