Programming TypeScript: Making Your JavaScript Applications Scale

Cover
Copyright
Table of Contents
Preface
	How This Book Is Organized
	Style
		Conventions Used in This Book
	Using Code Examples
	O’Reilly Online Learning
	How to Contact Us
	Acknowledgments
Chapter 1. Introduction
Chapter 2. TypeScript: A 10_000 Foot View
	The Compiler
	The Type System
		TypeScript Versus JavaScript
	Code Editor Setup
		tsconfig.json
		tslint.json
	index.ts
	Exercises
Chapter 3. All About Types
	Talking About Types
	The ABCs of Types
		any
		unknown
		boolean
		number
		bigint
		string
		symbol
		Objects
		Intermission: Type Aliases, Unions, and Intersections
		Arrays
		Tuples
		null, undefined, void, and never
		Enums
	Summary
	Exercises
Chapter 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
		Generic Type Defaults
	Type-Driven Development
	Summary
	Exercises
Chapter 5. Classes and Interfaces
	Classes and Inheritance
	super
	Using this as a Return Type
	Interfaces
		Declaration Merging
		Implementations
		Implementing Interfaces Versus Extending Abstract Classes
	Classes Are Structurally Typed
	Classes Declare Both Values and Types
	Polymorphism
	Mixins
	Decorators
	Simulating final Classes
	Design Patterns
		Factory Pattern
		Builder Pattern
	Summary
	Exercises
Chapter 6. Advanced Types
	Relationships Between Types
		Subtypes and Supertypes
		Variance
		Assignability
		Type Widening
		Refinement
	Totality
	Advanced Object Types
		Type Operators for Object Types
		The Record Type
		Mapped Types
		Companion Object Pattern
	Advanced Function Types
		Improving Type Inference for Tuples
		User-Defined Type Guards
	Conditional Types
		Distributive Conditionals
		The infer Keyword
		Built-in Conditional Types
	Escape Hatches
		Type Assertions
		Nonnull Assertions
		Definite Assignment Assertions
	Simulating Nominal Types
	Safely Extending the Prototype
	Summary
	Exercises
Chapter 7. Handling Errors
	Returning null
	Throwing Exceptions
	Returning Exceptions
	The Option Type
	Summary
	Exercises
Chapter 8. Asynchronous Programming, Concurrency, and Parallelism
	JavaScript’s Event Loop
	Working with Callbacks
	Regaining Sanity with Promises
	async and await
	Async Streams
		Event Emitters
	Typesafe Multithreading
		In the Browser: With Web Workers
		In NodeJS: With Child Processes
	Summary
	Exercises
Chapter 9. Frontend and Backend Frameworks
	Frontend Frameworks
		React
		Angular
	Typesafe APIs
	Backend Frameworks
	Summary
Chapter 10. Namespaces.Modules
	A Brief History of JavaScript Modules
	import, export
		Dynamic Imports
		Using CommonJS and AMD Code
		Module Mode Versus Script Mode
	Namespaces
		Collisions
		Compiled Output
	Declaration Merging
	Summary
	Exercise
Chapter 11. Interoperating with JavaScript
	Type Declarations
		Ambient Variable Declarations
		Ambient Type Declarations
		Ambient Module Declarations
	Gradually Migrating from JavaScript to TypeScript
		Step 1: Add TSC
		Step 2a: Enable Typechecking for JavaScript (Optional)
		Step 2b: Add JSDoc Annotations (Optional)
		Step 3: Rename Your Files to .ts
		Step 4: Make It strict
	Type Lookup for JavaScript
	Using Third-Party JavaScript
		JavaScript That Comes with Type Declarations
		JavaScript That Has Type Declarations on DefinitelyTyped
		JavaScript That Doesn’t Have Type Declarations on DefinitelyTyped
	Summary
Chapter 12. Building and Running TypeScript
	Building Your TypeScript Project
		Project Layout
		Artifacts
		Dialing In Your Compile Target
		Enabling Source Maps
		Project References
		Error Monitoring
	Running TypeScript on the Server
	Running TypeScript in the Browser
	Publishing Your TypeScript Code to NPM
	Triple-Slash Directives
		The types Directive
		The amd-module Directive
	Summary
Chapter 13. Conclusion
Appendix A. Type Operators
Appendix B. Type Utilities
Appendix C. Scoped Declarations
	Does It Generate a Type?
	Does It Merge?
Appendix D. Recipes for Writing Declaration Files for Third-Party JavaScript Modules
	Types of Exports
		Globals
		ES2015 Exports
		CommonJS Exports
		UMD Exports
	Extending a Module
		Globals
		Modules
Appendix E. Triple-Slash Directives
	Internal Directives
	Deprecated Directives
Appendix F. TSC Compiler Flags for Safety
Appendix G. TSX
Index
About the Author
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