Book Image

Professional JavaScript

By : Hugo Di Francesco, Siyuan Gao, Vinicius Isola, Philip Kirkbride
Book Image

Professional JavaScript

By: Hugo Di Francesco, Siyuan Gao, Vinicius Isola, Philip Kirkbride

Overview of this book

In depth knowledge of JavaScript makes it easier to learn a variety of other frameworks, including React, Angular, and related tools and libraries. This book is designed to help you cover the core JavaScript concepts you need to build modern applications. You'll start by learning how to represent an HTML document in the Document Object Model (DOM). Then, you'll combine your knowledge of the DOM and Node.js to create a web scraper for practical situations. As you read through further lessons, you'll create a Node.js-based RESTful API using the Express library for Node.js. You'll also understand how modular designs can be used for better reusability and collaboration with multiple developers on a single project. Later lessons will guide you through building unit tests, which ensure that the core functionality of your program is not affected over time. The book will also demonstrate how constructors, async/await, and events can load your applications quickly and efficiently. Finally, you'll gain useful insights into functional programming concepts such as immutability, pure functions, and higher-order functions. By the end of this book, you'll have the skills you need to tackle any real-world JavaScript development problem using a modern JavaScript approach, both for the client and server sides.
Table of Contents (12 chapters)

The Contents of a JWT

In the previous exercise, during step 7, we requested a token from the server and saved the value to our local Terminal session. For the exercise to have worked, the JWT should have the three parts separated by a period. If we take the JWT that was returned from our echo $TOKEN command and put it into the website, we can look at the contents of the JWT more closely.

Additionally, paste your secret value into the bottom-right corner of the GUI, which should display Signature Verified in the bottom-left corner. This tells us that the JWT being viewed was created using the private signature:

Figure 4.22: Showing with JWT data

The JWT website allows us to easily visualize what the three sections of the JWT represent. The first section in red is the header, that is, information that describes the encoding standard used. The purple section is the payload – it contains the data that was verified by the server when the...