What Is A Hook in ReactJS
✅ Hooks in ReactJS
Hooks are functions that allow you to use React features like state management, side effects, and context in functional components. They were introduced in React 16.8 to eliminate the need for class components.
📌 Why Use Hooks?
State Management → Manage state without using class components (
useState,useReducer).Side Effects → Perform actions like data fetching, DOM manipulation (
useEffect).Reusability → Create custom hooks for reusable logic (
useCustomHook).Simpler Code → Write cleaner, readable, and maintainable code using functional components.
📌 Basic Hooks in ReactJS
Here are some commonly used React Hooks:
| Hook | Purpose |
|---|---|
useState | Manage state in functional components |
useEffect | Perform side effects like API calls or DOM updates |
useContext | Access global state from a Context API |
useReducer | Manage complex state logic |
useRef | Access and manipulate DOM elements directly |
useMemo | Optimize performance by memoizing values |
useCallback | Optimize performance by memoizing functions |
useImperativeHandle | Customize the instance of a component using ref |
useLayoutEffect | Similar to useEffect, but fires synchronously after DOM changes |
useDebugValue | Add labels for custom hooks in React DevTools |
📌 1. Example of useState Hook
<ThemeContext.Provider <div> <div> <h1>Count: {state.count}</h1> <button onClick={() => dispatch({ type: 'increment' })}>Increment</button> <button onClick={() => dispatch({ type: 'decrement' })}>Decrement</button> </div> );};export default Counter;
🛠 Explanation:
useReducermanages state using actions and reducers.dispatchsends actions to update state.
📌 6. When to Use Hooks?
✅ Use Hooks when:
You are working with functional components.
You need to manage local state (
useState).You are handling side effects (
useEffect).You want to share state across components (
useContext).You are optimizing performance (
useMemo,useCallback).
❗ Avoid using Hooks when:
You are working with class components (Hooks are for functional components only).
You don't have stateful logic (Use a simple component instead).
📌 7. Conclusion
Hooks simplify state management and side effects in functional components.
They improve code readability and reusability.
Combine multiple hooks to build complex logic.
