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TypeScript

TypeScript for Beginners — Complete Free Tutorial

Learn TypeScript from zero with 24 original, hands-on chapters: annotations, interfaces, unions, narrowing, generics, classes, utility and mapped types, async typing, React integration, strict mode, testing and JavaScript migration. Every chapter includes code examples with expected output, common mistakes and a practice checklist.

This complete TypeScript course takes you from your first type annotation to a typed codebase you can ship. Each chapter is written for developers who already know JavaScript: plain-language explanations of what the compiler actually checks, copy-paste code examples with expected output, real compiler errors quoted exactly as TypeScript reports them, and internal links to related chapters. Follow the chapters in order or jump to any topic — by the end you will read a type and know what it allows, design interfaces and discriminated unions that make invalid states impossible, reach for generics and utility types without reaching for any, configure strict mode with confidence, and add types to an existing JavaScript project without breaking it.

Chapters

  1. 1. Introduction to TypeScript Read →
  2. 2. Setting Up TypeScript Read →
  3. 3. Basic Types and Annotations Read →
  4. 4. Arrays, Tuples and Objects Read →
  5. 5. Interfaces and Type Aliases Read →
  6. 6. Functions in TypeScript Read →
  7. 7. Union and Intersection Types Read →
  8. 8. Narrowing and Type Guards Read →
  9. 9. Literal Types and Enums Read →
  10. 10. any, unknown and never Read →
  11. 11. Generics Read →
  12. 12. Classes and Access Modifiers Read →
  13. 13. Utility Types Read →
  14. 14. keyof, Indexed Access and Mapped Types Read →
  15. 15. Conditional Types and infer Read →
  16. 16. Generics in Practice Read →
  17. 17. Modules, Declaration Files and d.ts Read →
  18. 18. Typing Async Code: Promises and Fetch Read →
  19. 19. TypeScript with React Read →
  20. 20. Strict Mode and tsconfig Deep Dive Read →
  21. 21. Error Handling and Result Types Read →
  22. 22. Testing with TypeScript Read →
  23. 23. Migrating JavaScript to TypeScript Read →
  24. 24. TypeScript Best Practices and Where to Go Next Read →