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
TypeScript Tools and Framework Options

Advanced types with generics

The TypeScript compiler already gives us a large toolbox in order to define custom types, inherit types from each other, and use generic syntax to describe how our code is expecting to use these types. By combining these language features, we can start to describe some seriously advanced type definitions, including types based on other types, or types based on some or all of the properties of another type. By using some new TypeScript keywords, and applying some well-known language features, we can also start to query a type for its properties, check to see whether a type has certain properties, or completely modify a type by adding or removing properties as we see fit. Welcome to the mind-bending world of conditional types, inferred types, mapped types and more, or as the author describes it, simply "theoretical type mathematics". Be warned...