Book Image

Learn TypeScript 3 by Building Web Applications

By : Sebastien Dubois, Alexis Georges
Book Image

Learn TypeScript 3 by Building Web Applications

By: Sebastien Dubois, Alexis Georges

Overview of this book

TypeScript is a superset of the JavaScript programming language, giving developers a tool to help them write faster, cleaner JavaScript. With the help of its powerful static type system and other powerful tools and techniques it allows developers to write modern JavaScript applications. This book is a practical guide to learn the TypeScript programming language. It covers from the very basics to the more advanced concepts, while explaining many design patterns, techniques, frameworks, libraries and tools along the way. You will also learn a ton about modern web frameworks like Angular, Vue.js and React, and you will build cool web applications using those. This book also covers modern front-end development tooling such as Node.js, npm, yarn, Webpack, Parcel, Jest, and many others. Throughout the book, you will also discover and make use of the most recent additions of the language introduced by TypeScript 3 such as new types enforcing explicit checks, flexible and scalable ways of project structuring, and many more breaking changes. By the end of this book, you will be ready to use TypeScript in your own projects and will also have a concrete view of the current frontend software development landscape.
Table of Contents (15 chapters)

Introducing testing

Testing is a very broad subject, and it deserves a lot more space than we can devote to it in this book. Here, we will merely be able to scratch the surface.

Code quality and testing

The population service of WorldExplorer might be coded defensively, but we should have proof that it will fail gracefully when issues arise.

Here are some examples of things that could go wrong:

  • The network could be down when we make a request or before we receive a result.
  • The server might be unavailable.
  • The server might return unexpected data (for example, missing data, incorrect types, HTTP errors, and many others​).
  • The code making use of the service could provide invalid input (for example, for the dateRange...