Express.js is a fast, minimalist web framework for Node.js that makes it easy to build and deploy web applications. With a small footprint, Express is designed to be flexible, scalable, and easy to use, making it a popular choice for building web applications and APIs.
Express allows developers to build web applications by creating routes and defining HTTP handlers that respond to requests. The framework provides a simple, yet powerful, API for handling incoming requests and sending responses. Express also integrates well with other Node.js libraries and packages, making it easy to extend the framework and build custom features.
One of the key features of Express is its middleware system. Middleware functions are small pieces of code that can be added to the request/response cycle to perform specific tasks. For example, middleware functions can be used for logging, authentication, error handling, and more. With this system, developers can easily add new functionality to their Express applications by adding new middleware functions.
Express also supports template engines, allowing developers to easily render dynamic HTML pages based on data from the server. Some of the most popular template engines used with Express include EJS, Jade, and Handlebars.
Another feature of Express is its ability to handle and route HTTP requests. With Express, developers can define multiple routes for handling different types of requests and return specific responses based on the incoming request. For example, a single Express application can handle multiple GET and POST requests, each with its own route and handler function.
In conclusion, Express.js is a popular and powerful web framework for Node.js that makes it easy to build and deploy web applications and APIs. With its fast, minimalist design, flexible middleware system, and support for template engines and routing, Express is a great choice for building dynamic web applications.