Book Image

Mastering TypeScript 3 - Third Edition

By : Nathan Rozentals
Book Image

Mastering TypeScript 3 - Third Edition

By: Nathan Rozentals

Overview of this book

TypeScript is both a language and a set of tools to generate JavaScript. It was designed by Anders Hejlsberg at Microsoft to help developers write enterprise-scale JavaScript. Starting with an introduction to the TypeScript language, before moving on to basic concepts, each section builds on previous knowledge in an incremental and easy-to-understand way. Advanced and powerful language features are all covered, including asynchronous programming techniques, decorators, and generics. This book explores many modern JavaScript and TypeScript frameworks side by side in order for the reader to learn their respective strengths and weaknesses. It will also thoroughly explore unit and integration testing for each framework. Best-of-breed applications utilize well-known design patterns in order to be scalable, maintainable, and testable. This book explores some of these object-oriented techniques and patterns, and shows real-world implementations. By the end of the book, you will have built a comprehensive, end-to-end web application to show how TypeScript language features, design patterns, and industry best practices can be brought together in a real-world scenario.
Table of Contents (16 chapters)
Free Chapter
1
TypeScript Tools and Framework Options

Advanced types

TypeScript also has some advanced language features that can be used when working with basic types and objects. These features allow us to mix and match types a little more, as well as to create new types that are combinations of other types. In this section of the chapter, we will take a quick look at these advanced type features, including the following:

  • Union types
  • Type guards
  • Type aliases
  • Null and undefined
  • Never and unknown
  • Object rest and spread
  • Tuples
  • BigInt

Union types

TypeScript allows us to express a type as the combination of two or more other types. These types are known as union types, and their declaration uses the pipe symbol (|) to list all of the types that will make up the new type. Consider...