Introduction

In the first chapter, we covered many of the new and powerful features released in ES6. We discussed the evolution of JavaScript and highlighted the key additions in ES6. We discussed scope rules, variable declaration, arrow functions, template literals, enhanced object properties, destructuring assignment, classes and modules, transpiling, and iterators and generators. In the second chapter, we covered JavaScript's asynchronous programming paradigm. We discussed the JavaScript event loop, callbacks, promises, and the async/await syntax. In the third chapter, we learned about the Document Object Model (DOM), the JavaScript Event object, and the jQuery library.

In this chapter, we will learn about testing code and code-testing frameworks in JavaScript. In the first topic, we will introduce testing and discuss test-driven development. Then, we will discuss applying test-driven development and several different ways you can test your code and applications. In the final topic, we...