From Ruby to TypeScript

Preface

Introduction

1. Who This Book Is For
2. How to Use This Book
3. What This Book Is Not
4. A Note on Runtime
5. About the Author

Chapter 1: Getting Started

1. Installing Node.js and a TypeScript Runner
2. Your First TypeScript Program
3. Template Literals: String Interpolation
4. Variables: const and let
5. Type Annotations (Your First Taste)
6. Functions
7. Arrow Functions
8. The Entry Point
9. tsconfig.json: Project Configuration
10. Chapter Exercises
11. Summary

Chapter 2: Types & Type Annotations

1. The Basic Types
2. Type Annotations
3. Type Inference
4. null and undefined
5. Union Types
6. Literal Types and Enums
7. Type Aliases
8. any and unknown
9. Type Assertions
10. Chapter Exercises
11. Summary

Chapter 3: Arrays, Tuples & Iteration

1. Typed Arrays
2. Mixed-Type Arrays
3. Tuples
4. readonly Arrays and Tuples
5. Iteration: for…of (The Each Replacement)
6. forEach: Each with an Index
7. Traditional for Loop (C-Style)
8. map: Transform Every Element
9. filter: Select Elements
10. reduce: Aggregate Values
11. some and every: Predicate Checks
12. Spread and Rest: The Splat Operator
13. Chapter Exercises
14. Summary

Chapter 4: Objects, Records & Maps

1. Object Types: The Hash Replacement
2. Optional Properties
3. Index Signatures: Hash-Like Objects
4. Record: Typed Hash
5. Map: When Keys Are Dynamic
6. Set: Unique Collections
7. Object Destructuring: Hash Splat
8. Spread: Merging Objects
9. readonly Properties
10. Chapter Exercises
11. Summary

Chapter 5: Functions Deep Dive

1. Function Declarations vs Arrow Functions
2. Typed Parameters and Return Types
3. Optional and Default Parameters
4. Rest Parameters: Ruby’s Splat
5. Callbacks and Function Types
6. Void and Never Return Types
7. Function Overloads
8. Chapter Exercises
9. Summary

Chapter 6: Classes

1. A Ruby Class, Translated
2. Access Modifiers: public, private, protected
3. JavaScript Private Fields (#)
4. Parameter Properties (Shorthand)
5. Inheritance: extends
6. Abstract Classes
7. Getters and Setters
8. this and Arrow Functions
9. Chapter Exercises
10. Summary

Chapter 7: Interfaces & Type Aliases

1. Interfaces: The Basics
2. interface vs type
3. Extending Interfaces
4. Optional and readonly Properties in Interfaces
5. Index Signatures in Interfaces
6. Structural Typing in Practice
7. When Interfaces Feel Like Ruby Modules
8. Chapter Exercises
9. Summary

Chapter 8: Modules & Package Management

1. import and export: The New require
2. Named Exports vs Default Exports
3. Re-exports and Barrel Files
4. package.json: The Gemfile
5. npm, Yarn, and pnpm
6. node_modules and the Magic of Resolution
7. Your First TypeScript Project (Walkthrough)
8. tsconfig.json Paths: Module Aliases
9. Installing Type Definitions
10. Chapter Exercises
11. Summary

Chapter 9: Error Handling

1. try/catch/finally: The Direct Mapping
2. Typed Catch with instanceof
3. Custom Error Classes
4. The TypeScript Way: Errors as Values
5. Strict Null Checks: Eliminating NoMethodError on nil
6. Optional Chaining: Safe Navigation
7. Nullish Coalescing: The || Alternative
8. Chapter Exercises
9. Summary

Chapter 10: Async Programming

1. The Event Loop
2. Callbacks and Callback Hell
3. Promises: The Foundation
4. async/await: Write Async Code That Looks Synchronous
5. The async Main Function
6. Async Iteration
7. Ruby Threads vs TypeScript Promises
8. Chapter Exercises
9. Summary

Chapter 11: JSON & Type Narrowing

1. JSON.stringify: Value to JSON
2. JSON.parse: JSON to Value (and the any Problem)
3. Type Assertions: Trust Me
4. Type Guards: Prove It at Runtime
5. Zod: Schema Validation
6. Discriminated Unions: The JSON Pattern
7. Working with Unknown JSON Shapes
8. Chapter Exercises
9. Summary

Chapter 12: Generics & Utility Types

1. The Problem Generics Solve
2. Generic Functions
3. Generic Interfaces and Types
4. Generic Constraints
5. Built-in Utility Types
6. Generics vs Duck Typing
7. Chapter Exercises
8. Summary

Appendix A: Ruby ↔ TypeScript Quick Reference

1. Syntax & Structure
2. Variables & Types
3. Data Structures
4. Functions & Methods
5. Error Handling
6. Concurrency & Async
7. Modules & Packages
8. Common Patterns
9. TypeScript CLI Cheat Sheet
10. File Layout

Glossary

Acknowledgements

Credits