ReactJS Program to useDebouncedValue Hook with Explanation
ReactJS
Hard
Hooks & Effects
29 views
1 min read
88 words
This problem helps you practice core ReactJS fundamentals in a practical way. It builds intuition around hook, react, usedebouncedvalue. Let’s break it down step by step so you can implement it confidently.
Problem Statement
Create a hook that debounces a value and updates after a delay.
Input Format
No input.
Output Format
Render a React component.
Constraints
Use useEffect + setTimeout and clean it up on change.
Code Solution
This explanation is written for learning purposes and to help beginners understand the concept clearly.
import React, { useEffect, useState } from 'react';
function useDebouncedValue(value, delayMs) {
const [debounced, setDebounced] = useState(value);
useEffect(() => {
const id = setTimeout(() => setDebounced(value), delayMs);
return () => clearTimeout(id);
}, [value, delayMs]);
return debounced;
}
export default function App() {
const [query, setQuery] = useState('');
const debounced = useDebouncedValue(query, 450);
return (
<div style={{ padding: 16, width: 520 }}>
<h2 style={{ marginTop: 0 }}>meetcode search</h2>
<input value={query} onChange={(e) => setQuery(e.target.value)} placeholder='Type to search...' style={{ width: '100%', padding: '10px 12px', borderRadius: 12, border: '1px solid #bbb' }} />
<div style={{ marginTop: 10, color: '#555' }}>Debounced: {debounced || '...'}</div>
</div>
);
}
Output Example
No sample I/O is provided for this question.
Common Mistakes
- Misreading input/output format.
- Not handling constraints and edge cases.
- Off-by-one errors in loops.
- Forgetting to reset variables between test cases (if any).
Solution Guide
Problem
Create a hook that debounces a value and updates after a delay.
Input / Output
Output
Render a React component.
Constraints
Use useEffect + setTimeout and clean it up on change.
Details
Common Mistakes
- Misreading input/output format.
- Not handling constraints and edge cases.
- Off-by-one errors in loops.
- Forgetting to reset variables between test cases (if any).
Official Solution
import React, { useEffect, useState } from 'react';
function useDebouncedValue(value, delayMs) {
const [debounced, setDebounced] = useState(value);
useEffect(() => {
const id = setTimeout(() => setDebounced(value), delayMs);
return () => clearTimeout(id);
}, [value, delayMs]);
return debounced;
}
export default function App() {
const [query, setQuery] = useState('');
const debounced = useDebouncedValue(query, 450);
return (
<div style={{ padding: 16, width: 520 }}>
<h2 style={{ marginTop: 0 }}>meetcode search</h2>
<input value={query} onChange={(e) => setQuery(e.target.value)} placeholder='Type to search...' style={{ width: '100%', padding: '10px 12px', borderRadius: 12, border: '1px solid #bbb' }} />
<div style={{ marginTop: 10, color: '#555' }}>Debounced: {debounced || '...'}</div>
</div>
);
}
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