Introduction to Custom Hooks

Custom hooks are a powerful pattern in React that allow you to extract and reuse stateful logic between components. They are regular JavaScript functions that can call other hooks.

Why Custom Hooks?

When you find yourself repeating the same stateful logic across multiple components, it's time to extract it into a custom hook:

Custom Hooks to the Rescue

By extracting shared logic into a custom hook, we get clean, reusable code:

Rules for Custom Hooks

Custom hooks must follow specific naming and usage rules:

Anatomy of a Custom Hook

Let's break down the structure of a custom hook:

Simple Example: useToggle

A toggle hook is one of the simplest and most useful custom hooks:

Exercise: Create useCounter Hook

Exercise: Create useInput Hook

Exercise: Create usePrevious Hook

Key Takeaways

1. Custom hooks extract reusable logic - Move repeated stateful logic into a single hook
2. Must start with "use" - This naming convention tells React it's a hook
3. Can call other hooks - Custom hooks can use useState, useEffect, and other hooks
4. Return what's needed - Return values, functions, or objects that components need
5. Keep hooks focused - Each hook should do one thing well
6. Follow the rules - Only call hooks at the top level and from React functions