ReactJS
Essential React Hooks Every Developer Must Master in 2025
Introduction
React hooks have revolutionized the way we write functional components, making state management and side effects much more intuitive. If you're learning React, understanding these essential hooks is a must! In this blog, we'll break down the most important hooks with examples so you can easily grasp their usage.
What Are React Hooks?
React Hooks are built in functions that allow functional components to manage state and lifecycle features previously only available in class components. Introduced in React 16.8, hooks enable developers to write cleaner, reusable and more maintainable code without needing class components.
Why Use Hooks?
- Simplifies State Management: Hooks allow functional components to have state, eliminating the need for class components.
- Improves Code Reusability: Logic can be shared across components using custom hooks.
- Handles Side Effects Easily: Hooks like useEffect help manage data fetching, DOM manipulation and subscriptions.
- Enhances Performance: Hooks like useMemo and useCallback help optimize performance by preventing unnecessary re renders.
- Provides Better Readability: The functional approach makes code easier to read and maintain.
1. useState - Managing Component State
The useState hook allows functional components to manage state. It returns an array with two elements: the current state and a function to update that state.
Why use useState?
- It helps store values that change over time, such as user inputs, toggle states, or counters.
- It ensures component re-renders when the state is updated.
import React, { useState } from 'react';function Counter() {const [count, setCount] = useState(0);return (<div><p>Count: {count}</p><button onClick={() => setCount(count + 1)}>Increase</button></div>);}2. useEffect - Handling Side Effects
The useEffect hook is used to handle side effects such as fetching data, subscribing to events or manually changing the DOM. It runs after the component renders.
Why use useEffect?
- It replaces lifecycle methods like componentDidMount, componentDidUpdate and componentWillUnmount.
- It helps fetch and update data asynchronously without blocking rendering.
import React, { useState, useEffect } from 'react';function Timer() {const [seconds, setSeconds] = useState(0);useEffect(() => {const interval = setInterval(() => {setSeconds(prev => prev + 1);}, 1000);return () => clearInterval(interval);}, []);return <p>Timer: {seconds} seconds</p>;}3. useContext - Avoiding Prop Drilling
The useContext hook allows components to consume context values without manually passing props through intermediate components.
Why use useContext?
- It eliminates prop drilling by providing direct access to global state.
- It simplifies state management when used with React.createContext().
import React, { useContext, createContext } from 'react';const ThemeContext = createContext('light');function ThemedComponent() {const theme = useContext(ThemeContext);return <p>Current Theme: {theme}</p>;}4. useRef - Accessing DOM Elements and Persisting Values
The useRef hook is used to persist values across renders without causing re-renders. It is also useful for directly interacting with DOM elements.
Why use useRef?
- It helps access and manipulate DOM elements without re-rendering.
- It retains values across renders, making it useful for timers and tracking previous values.
5. useReducer - Managing Complex State
The useReducer hook is used for managing complex state logic, similar to Redux, by dispatching actions to update state.
Why use useReducer?
- It’s ideal for handling state transitions with multiple actions.
- It provides a predictable state management pattern.
import React, { useReducer } from 'react';const initialState = { count: 0 };function reducer(state, action) {switch (action.type) {case 'increment':return { count: state.count + 1 };case 'decrement':return { count: state.count - 1 };default:return state;}}function Counter() {const [state, dispatch] = useReducer(reducer, initialState);return (<div><p>Count: {state.count}</p><button onClick={() => dispatch({ type: 'increment' })}>+</button><button onClick={() => dispatch({ type: 'decrement' })}>-</button></div>);}6. useMemo - Optimizing Performance
The useMemo hook memoizes a computed value to prevent expensive calculations on every render.
Why use useMemo?
- It optimizes performance by avoiding unnecessary recalculations.
- It is useful when performing expensive operations based on dependencies.
import React, { useMemo } from 'react';function ExpensiveCalculation({ num }) {const result = useMemo(() => {console.log('Calculating...');return num * 2;}, [num]);return <p>Double: {result}</p>;}
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ReactJS