What is Express?
Express is a relatively small framework that sits on top of Node.js’s web server functionality to simplify its APIs and add helpful new features. It makes it easier to organize your application’s functionality with middleware and routing; it adds helpful utilities to Node.js’s HTTP objects; it facilitates the rendering of dynamic HTML views; it defines an easily-implemented extensibility standard. This book explores those features in a lot more depth, so all of that lingo will be demystified soon.
What Express is used for?
In theory, Express could be used to build any web application. It can process incoming requests and respond to them, so it can do things that you can do in most of the other frameworks mentioned above. Why would you choose Express over something else?
developers, they can whip up a simple SPA server without too much new learning.
When you write applications with Express, you can’t get away from using Node.js, so you’re going to have the “E” and the “N” parts of the MEAN stack, but the other two parts (MongoDB and Angular) are up to you because Express is unopinionated. Want to replace Angular with Backbone.js on the frontend? Now it’s the MEBN stack. Want to use SQL instead of MongoDB? Now it’s the SEAN stack. While MEAN is a common bit of lingo thrown around
and a popular configuration, you can choose whichever you want. In this book, we’ll cover the MongoDB database, so we’ll get the “MEN” stack.
Express also fits in side-by-side with a lot of real-time features. While other programming environments can support real-time features like WebSockets and WebRTC, Node.js seems to get more of that than other languages and frameworks. That means that you can Because Node gets it, Express gets it too.