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)

End-to-End Testing

While integration testing combines multiple units or functions of a software project, end-to-end testing goes one step further by simulating the actual use of the software.

For example, while our unit tests directly called functions such as math.square, an end-to-end test would load the graphical interface of the calculator and simulate pressing a number, say 5, followed by the square button. After a few seconds, the end-to-end test would look at the resulting answer in the graphical interface and ensure it equals 25 as expected.

End-to-end testing should be used more sparingly due to the overhead, but it is a great final step in a testing process to ensure that everything is working as expected. In contrast, unit tests are relatively quick to run and, therefore, can be run more often without slowing down development. The following figure shows a recommended distribution of tests:

Figure 6.7: Recommended distribution of tests