Effective TypeScript
by Based on Dan Vanderkam's Book
Master TypeScript with 62 specific ways to improve your TypeScript. Learn type system fundamentals, type inference, type design patterns, and best practices for writing robust, maintainable TypeScript code.
Last updated: 2026-02-05
Chapters
This guide covers the following chapters. Work through them in order for the best learning experience.
Understanding TypeScript
The relationship between TypeScript and JavaScript, and how the type system works
TypeScript's Type System
Core concepts of the type system including structural typing and type narrowing
Type Inference
How TypeScript infers types and when to provide explicit annotations
Type Design
Designing types that are precise, helpful, and prevent bugs
Working with any
Strategies for using any safely and minimizing its scope
Type Declarations and @types
Writing and using type declarations for third-party libraries
Writing and Running Your Code
Practical patterns for writing TypeScript in real applications
Migrating to TypeScript
Strategies for converting JavaScript codebases to TypeScript
Generics and Type Parameters
Writing flexible, reusable code with generic types
Conditional Types and Mapped Types
Advanced type-level programming with conditional and mapped types
Built-in Utility Types
Mastering TypeScript's built-in utility types for common transformations
Type Guards and Assertions
Runtime type checking and narrowing with type guards
Modules and Namespaces
Organizing TypeScript code with modules and understanding namespaces
Declaration Files Deep Dive
Creating .d.ts files and ambient declarations
Strict Mode and Compiler Options
Configuring TypeScript for maximum type safety