Programming TypeScript: making your JavaScript applications scale

Any programmer working with a dynamically typed language will tell you how hard it is to scale to more lines of code and more engineers. That's why Facebook, Google, and Microsoft invented gradual static type layers for their dynamically typed JavaScript and Python code. This practical book shows you how one such type layer, TypeScript, is unique among them: it makes programming fun with its powerful static type system. If you're a programmer with intermediate JavaScript experience, author Boris Cherny will teach you how to master the TypeScript language. You'll understand how TypeScript can help you eliminate bugs in your code and enable you to scale your code across more engineers than you could before. In this book, you'll:Start with the basics: Learn about TypeScript's different types and type operators, including what they're for and how they're usedExplore advanced topics: Understand TypeScript's sophisticated type system, including how to safely handle errors and build asynchronous programsDive in hands-on: Use TypeScript with your favorite frontend and backend frameworks, migrate your existing JavaScript project to TypeScript, and run your TypeScript application in production

Includes index.

Intro; Preface; How This Book Is Organized; Style; Conventions Used in This Book; Using Code Examples; O'Reilly Online Learning; How to Contact Us; Acknowledgments; 1. Introduction; 2. TypeScript: A 10_000 Foot View; The Compiler; The Type System; TypeScript Versus JavaScript; How are types bound?; Are types automatically converted?; When are types checked?; When are errors surfaced?; Code Editor Setup; tsconfig.json; tslint.json; index.ts; Exercises; 3. All About Types; Talking About Types; The ABCs of Types; any; unknown; boolean; number; bigint; string; symbol; Objects

Intermission: Type Aliases, Unions, and IntersectionsType aliases; Union and intersection types; Arrays; Tuples; Read-only arrays and tuples; null, undefined, void, and never; Enums; Summary; Exercises; 4. Functions; Declaring and Invoking Functions; Optional and Default Parameters; Rest Parameters; call, apply, and bind; Typing this; Generator Functions; Iterators; Call Signatures; Contextual Typing; Overloaded Function Types; Polymorphism; When Are Generics Bound?; Where Can You Declare Generics?; Generic Type Inference; Generic Type Aliases; Bounded Polymorphism

Bounded polymorphism with multiple constraints…