Create a counter component using useState and useReducer in React.

Question

Create a counter component using useState and useReducer in React.

Answer

Using useState (simple)

import { useState } from 'react';

function CounterState() {
  const [count, setCount] = useState(0);
  return (
    <div>
      <p>Count: {count}</p>
      <button onClick={() => setCount(count + 1)}>+</button>
      <button onClick={() => setCount(count - 1)}>-</button>
    </div>
  );
}

Using useReducer (structured)

import { useReducer } from 'react';

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 CounterReducer() {
  const [state, dispatch] = useReducer(reducer, { count: 0 });

  return (
    <div>
      <p>Count: {state.count}</p>
      <button onClick={() => dispatch({ type: 'increment' })}>+</button>
      <button onClick={() => dispatch({ type: 'decrement' })}>-</button>
    </div>
  );
}

✅ useReducer gives more control for complex state transitions — great for forms, multiple counters, or UI state management.

Real-World Example

• Cart quantity in e-commerce
• Step-based forms
• Complex UI toggles

Quick Practice

Implement a ScoreCounter using useReducer with “reset” and “bonus +5” actions.

Summary

Use useState for simple updates, and useReducer when managing structured or multi-step state.