Book Image

MERN Quick Start Guide

By : Eddy Wilson Iriarte Koroliova
3 (1)
Book Image

MERN Quick Start Guide

3 (1)
By: Eddy Wilson Iriarte Koroliova

Overview of this book

The MERN stack is a collection of great tools—MongoDB, Express.js, React, and Node—that provide a strong base for a developer to build easily maintainable web applications. With each of them a JavaScript or JavaScript-based technology, having a shared programming language means it takes less time to develop web applications. This book focuses on providing key tasks that can help you get started, learn, understand, and build full-stack web applications. It walks you through the process of installing all the requirements and project setup to build client-side React web applications, managing synchronous and asynchronous data flows with Redux, and building real-time web applications with Socket.IO, RESTful APIs, and other concepts. This book gives you practical and clear hands-on experience so you can begin building a full-stack MERN web application. Quick Start Guides are focused, shorter titles that provide a faster paced introduction to a technology. They are for people who don't need all the detail at this point in their learning curve. The presentation has been streamlined to concentrate on the things you really need to know.
Table of Contents (8 chapters)

Writing middleware for Socket.IO

Socket.IO allows us to define two kinds of middleware functions in the server side:

  • Namespace middleware: Registers a function that gets executed for every new connected Socket and has the following signature:
      namespace.use((socket, next) => { ... }) 
  • Socket middleware: Registers a function that gets executed for every incoming Packet and has the following signature:
      socket.use((packet, next) => { ... }) 

It works similarly to how ExpressJS middleware functions do. We can add new properties to the socket or packet objects. Then, we can call next to pass the control to the next middleware in the chain. If next is not called, then the socket won't be connected, or the packet received.

Getting ready