Tackling TypeScript

I Preliminaries
- 1 About this book
  - 1.1 Where is the homepage of this book?
  - 1.2 What is in this book?
  - 1.3 What do I get for my money?
  - 1.4 How can I preview the content?
  - 1.5 How do I report errors?
  - 1.6 What do the notes with icons mean?
  - 1.7 Acknowledgements
- 2 Why TypeScript?
  - 2.1 The benefits of using TypeScript
  - 2.2 The downsides of using TypeScript
  - 2.3 TypeScript myths
- 3 Free resources on TypeScript
II Getting started with TypeScript
- 4 How does TypeScript work? The bird’s eye view
  - 4.1 The structure of TypeScript projects
  - 4.2 Programming TypeScript via an integrated development environment (IDE)
  - 4.3 Other files produced by the TypeScript compiler
  - 4.4 Using the TypeScript compiler for plain JavaScript files
- 5 Trying out TypeScript
  - 5.1 The TypeScript Playground
  - 5.2 TS Node
- 6 Notation used in this book
  - 6.1 Test assertions (dynamic)
  - 6.2 Type assertions (static)
- 7 The essentials of TypeScript
  - 7.1 What you’ll learn
  - 7.2 Specifying the comprehensiveness of type checking
  - 7.3 Types in TypeScript
  - 7.4 Type annotations
  - 7.5 Type inference
  - 7.6 Specifying types via type expressions
  - 7.7 The two language levels: dynamic vs. static
  - 7.8 Type aliases
  - 7.9 Typing Arrays
  - 7.10 Function types
  - 7.11 Union types
  - 7.12 Optional vs. default value vs. undefined|T
  - 7.13 Typing objects
  - 7.14 Type variables and generic types
  - 7.15 Example: a generic class
  - 7.16 Conclusion: understanding the initial example
- 8 Creating CommonJS-based npm packages via TypeScript
  - 8.1 Required knowledge
  - 8.2 Limitations
  - 8.3 The repository ts-demo-npm-cjs
  - 8.4 .gitignore
  - 8.5 .npmignore
  - 8.6 package.json
  - 8.7 tsconfig.json
  - 8.8 TypeScript code
- 9 Creating web apps via TypeScript and webpack
  - 9.1 Required knowledge
  - 9.2 Limitations
  - 9.3 The repository ts-demo-webpack
  - 9.4 package.json
  - 9.5 webpack.config.js
  - 9.6 tsconfig.json
  - 9.7 index.html
  - 9.8 main.ts
  - 9.9 Installing, building and running the web app
  - 9.10 Using webpack without a loader: webpack-no-loader.config.js
- 10 Strategies for migrating to TypeScript
  - 10.1 Three strategies
  - 10.2 Strategy: mixed JavaScript/TypeScript code bases
  - 10.3 Strategy: adding type information to plain JavaScript files
  - 10.4 Strategy: migrating large projects by snapshot testing the TypeScript errors
  - 10.5 Conclusion
III Basic types
- 11 What is a type in TypeScript? Two perspectives (bonus)
  - 11.1 Two questions for each perspective
  - 11.2 Perspective 1: types are sets of values
  - 11.3 Perspective 2: type compatibility relationships
  - 11.4 Nominal type systems vs. structural type systems
  - 11.5 Further reading
- 12 The top types any and unknown
  - 12.1 TypeScript’s two top types
  - 12.2 The top type any
  - 12.3 The top type unknown
- 13 TypeScript enums: How do they work? What can they be used for?
  - 13.1 The basics
  - 13.2 Specifying enum member values (advanced)
  - 13.3 Downsides of numeric enums
  - 13.4 Use cases for enums
  - 13.5 Enums at runtime
  - 13.6 const enums
  - 13.7 Enums at compile time
  - 13.8 Acknowledgment
- 14 Alternatives to enums in TypeScript
  - 14.1 Unions of singleton values
  - 14.2 Discriminated unions
  - 14.3 Object literals as enums
  - 14.4 Enum pattern
  - 14.5 Summary of enums and enum alternatives
  - 14.6 Acknowledgement
- 15 Adding special values to types
  - 15.1 Adding special values in band
  - 15.2 Adding special values out of band
IV Types for objects, classes, Arrays, and functions
- 16 Typing objects
  - 16.1 Roles played by objects
  - 16.2 Types for objects
  - 16.3 Object vs. object in TypeScript
  - 16.4 Object type literals and interfaces
  - 16.5 Type inference
  - 16.6 Other features of interfaces
  - 16.7 JavaScript’s prototype chains and TypeScript’s types
  - 16.8 Sources of this chapter
- 17 Class definitions in TypeScript
  - 17.1 Cheat sheet: classes in plain JavaScript
  - 17.2 Non-public data slots in TypeScript
  - 17.3 Private constructors
  - 17.4 Initializing instance properties
  - 17.5 Abstract classes
- 18 Class-related types
  - 18.1 The two prototype chains of classes
  - 18.2 Interfaces for instances of classes
  - 18.3 Interfaces for classes
  - 18.4 Classes as types
  - 18.5 Further reading
- 19 Types for classes as values
  - 19.1 Types for specific classes
  - 19.2 The type operator typeof
  - 19.3 A generic type for classes: Class<T>
- 20 Typing Arrays
  - 20.1 Roles of Arrays
  - 20.2 Ways of typing Arrays
  - 20.3 Pitfall: type inference doesn’t always get Array types right
  - 20.4 Pitfall: TypeScript assumes indices are never out of bounds
- 21 Typing functions
  - 21.1 Defining statically typed functions
  - 21.2 Types for functions
  - 21.3 Parameters
  - 21.4 Overloading (advanced)
  - 21.5 Assignability (advanced)
  - 21.6 Further reading and sources of this chapter
V Dealing with ambiguous types
- 22 Type assertions (related to casting)
  - 22.1 Type assertions
  - 22.2 Constructs related to type assertions
- 23 Type guards and assertion functions
  - 23.1 When are static types too general?
  - 23.2 Narrowing via built-in type guards
  - 23.3 User-defined type guards
  - 23.4 Assertion functions
  - 23.5 Quick reference: user-defined type guards and assertion functions
  - 23.6 Alternatives to assertion functions
  - 23.7 @hqoss/guards: library with type guards
- 24 Validating external data (bonus)
  - 24.1 JSON schema
  - 24.2 Approaches for data validation in TypeScript
  - 24.3 Example: validating data via the library Zod
  - 24.4 Conclusion
VI Miscellaneous
- 25 An overview of computing with types
  - 25.1 Types as metavalues
  - 25.2 Generic types: factories for types
  - 25.3 Union types and intersection types
  - 25.4 Control flow
  - 25.5 Various other operators

Tackling TypeScript

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