🔍 Overview
Chapter 5 dives into function types—how functions are represented and enforced in a type system. It explains how TypeScript uses types to describe function signatures, enabling safer and more predictable code.
💡 Key Concepts
- Function Signatures: Defines how parameter types and return types form a function’s type.
- Optional and Default Parameters: Shows how to handle functions with flexible inputs.
- Rest Parameters: Explains how to accept variable-length arguments using `...args` syntax.
- Function Overloading: Demonstrates how to define multiple call signatures for a single function.
- Higher-Order Functions: Introduces functions that take other functions as arguments or return them.
- Callback Types: Covers how to type functions passed as arguments to other functions.
🧭 Takeaway
Understanding function types is essential for writing expressive and reusable TypeScript code. They allow developers to encode behavior, enforce contracts, and build powerful abstractions with confidence.