A Simple Guide to Express.js for Beginners

What is a JavaScript Framework?

• A JavaScript framework is a set of JavaScript code libraries that provide pre-written code for everyday programming tasks to a web developer.

• Frameworks have a specific context and aid in creating web applications within that context.

• They provide you with a great deal of control over your app.

• They may also point you in the right direction regarding architecture, and the project that follows.

• There are approximately 24 JavaScript frameworks available.

• Express.js is one of the best JavaScript frameworks available

What are JavaScript Libraries?

• A JS library is a piece of reusable code with a single primary use case.

• A JavaScript library can have multiple functions/objects/methods depending on the language.

• To have access to that capability, your application will link to a library.

• JavaScript libraries remove the need to reinvent the wheel for certain bits of code.

• As a result, development is more efficient and error-free.

• jQuery library is a powerful, lightweight, and feature-rich open-source JavaScript library

What is Express.js ?

• 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.

• ou can assume express as a layer built on the top of the Node.js that helps manage a server and routes.

• It provides a robust set of features to develop web and mobile applications.

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.

Key Features of Express :

1. Middleware and Routing: Define clear pathways (routes) within your application to handle incoming HTTP requests (GET, POST, PUT, DELETE) with ease. Implement reusable functions (middleware) to intercept requests and create responses, adding functionalities like authentication, logging, and data parsing.

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. Templating Power: Incorporate templating engines like Jade or EJS to generate dynamic HTML content, enhancing user experience.

5. Static File Serving: Effortlessly serve static files like images, CSS, and JavaScript from a designated directory within your application.

6. Node.js Integration: Express.js seamlessly integrates with the core functionalities of Node.js, allowing you to harness the power of asynchronous programming and event-driven architecture

Features of Express framework In Short:

• It can be used to design single-page, multi-page and hybrid web applications.

• It allows to setup middlewares to respond to HTTP Requests.

• It defines a routing table which is used to perform different actions based on HTTP method and URL.

• It allows to dynamically render HTML Pages based on passing arguments to templates.

Why use Express:

• Ultra fast I/O

• Asynchronous and single threaded

• MVC like structure

• Robust API makes routing easy

Getting Started Express:

1. Installation: Install Express using npm:

npm install express

2. Basic Example of an Express App:

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.

Applications of Express :

Express.js empowers you to construct a wide array of web applications. Here are some captivating examples:

• RESTful APIs: Develop robust APIs that adhere to the REST architectural style, enabling communication with other applications and front-end interfaces.

• Real-time Applications: Leverage Express.js’s event-driven nature to create real-time applications like chat or collaborative editing tools.

• Single-Page Applications (SPAs): Craft SPAs that fetch and update content dynamically on the client-side, offering a seamless user experience.