Learn to build web applications using Node.js and the Express framework.

Become a MEAN Stack Developer

Node.js is a runtime environment that enables JavaScript to run outside the browser. In this module, we'll learn the fundamentals of Node.js to build portable applications. We'll learn about the components of Node.js and make patterns using these. We'll also explore the API to learn how to create modules and write code for unique data files. Moreover, we'll delve into the features and practices of JavaScript and build a REST API using the Express framework from scratch. Moving on, we'll use Passport.js and JSON web tokens to establish authentication tokens. We’ll then create a live trivia game with Socket.IO. By the end of this module, we'll be equipped with extensive knowledge to build rich and comprehensive Node.js applications running on the server with JavaScript.

Learn Node.js from Scratch

## Key takeaways
Let’s take a moment to reflect on what we’ve learned in this chapter:

- AJAX polling is a technique applied in AJAX applications where the client opens a connection with the server and then repeatedly sends HTTP requests to a server at regular intervals to get any new information the server has.
- In long polling, the client opens a connection with the server and makes an initial HTTP request but doesn’t expect the server to respond immediately.
- WebSocket creates a persistent, bidirectional communication session between the user’s browser and a web server. Socket.IO can be used to build various applications with real-time communication capabilities, such as streaming applications, document collaboration, and instant messaging. Socket.IO uses WebSocket as a means of transport when the WebSocket API is available in the browser, falling back on HTTP long polling if it’s not.
- Socket.IO uses events to facilitate data transfer between the client and the server. Every event consists of two sides, the sender and the receiver. If the server is the sender, then the client is the receiver. If the client is the sender, then the server is the receiver.

# Key takeaways
Let’s take a moment to reflect on what we’ve learned in this chapter:

- AJAX polling is a technique applied in AJAX applications where the client opens a connection with the server and then repeatedly sends HTTP requests to a server at regular intervals to get any new information the server has.
- In long polling, the client opens a connection with the server and makes an initial HTTP request but doesn’t expect the server to respond immediately.
- WebSocket creates a persistent, bidirectional communication session between the user’s browser and a web server. Socket.IO can be used to build various applications with real-time communication capabilities, such as streaming applications, document collaboration, and instant messaging. Socket.IO uses WebSocket as a means of transport when the WebSocket API is available in the browser, falling back on HTTP long polling if it’s not.
- Socket.IO uses events to facilitate data transfer between the client and the server. Every event consists of two sides, the sender and the receiver. If the server is the sender, then the client is the receiver. If the client is the sender, then the server is the receiver.

Let's highlight the main contents of this chapter.

Node.js Overview

The Node.js API

JavaScript Essentials Review

Building a RESTful API with Express

Authentication with Passport.js and JSON Web Tokens

Build a Live Trivia Game with Socket.IO

Appendix

Conclusion

Wrap Up

Key takeaways