ReactJS Program to Request Status State with Explanation
ReactJS
Hard
State Management
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1 min read
91 words
This problem helps you practice core ReactJS fundamentals in a practical way. It builds intuition around status, state, data. Let’s break it down step by step so you can implement it confidently.
Problem Statement
Build a card that loads data and shows idle/loading/success/error states.
Input Format
No input.
Output Format
Render a React component.
Constraints
Store status and data separately and switch UI by status.
Code Solution
This explanation is written for learning purposes and to help beginners understand the concept clearly.
import React, { useEffect, useState } from 'react';
function fakeLoad() {
return new Promise((resolve, reject) => {
setTimeout(() => {
const ok = Math.random() > 0.25;
if (ok) resolve({ user: 'Meetcode Learner', streak: 7 });
else reject(new Error('Server busy'));
}, 650);
});
}
export default function App() {
const [status, setStatus] = useState('idle');
const [data, setData] = useState(null);
const [error, setError] = useState('');
async function load() {
setStatus('loading');
setError('');
setData(null);
try {
const res = await fakeLoad();
setData(res);
setStatus('success');
} catch (e) {
setError(String(e.message || e));
setStatus('error');
}
}
useEffect(() => {
load();
}, []);
return (
<div style={{ padding: 16, width: 520 }}>
<h2 style={{ marginTop: 0 }}>meetcode profile</h2>
<button type='button' onClick={load} disabled={status === 'loading'} style={{ padding: '8px 12px', borderRadius: 12, border: '1px solid #ddd', background: '#fff' }}>Reload</button>
<div style={{ marginTop: 12, border: '1px solid #eee', borderRadius: 16, padding: 14 }}>
{status === 'idle' ? <div style={{ color: '#555' }}>Click reload.</div> : null}
{status === 'loading' ? <div>Loading...</div> : null}
{status === 'error' ? <div style={{ color: '#c1121f' }}>{error}</div> : null}
{status === 'success' ? (
<div>
<div><strong>{data.user}</strong></div>
<div style={{ color: '#555', marginTop: 6 }}>Streak: {data.streak} days</div>
</div>
) : null}
</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
Build a card that loads data and shows idle/loading/success/error states.
Input / Output
Output
Render a React component.
Constraints
Store status and data separately and switch UI by status.
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 fakeLoad() {
return new Promise((resolve, reject) => {
setTimeout(() => {
const ok = Math.random() > 0.25;
if (ok) resolve({ user: 'Meetcode Learner', streak: 7 });
else reject(new Error('Server busy'));
}, 650);
});
}
export default function App() {
const [status, setStatus] = useState('idle');
const [data, setData] = useState(null);
const [error, setError] = useState('');
async function load() {
setStatus('loading');
setError('');
setData(null);
try {
const res = await fakeLoad();
setData(res);
setStatus('success');
} catch (e) {
setError(String(e.message || e));
setStatus('error');
}
}
useEffect(() => {
load();
}, []);
return (
<div style={{ padding: 16, width: 520 }}>
<h2 style={{ marginTop: 0 }}>meetcode profile</h2>
<button type='button' onClick={load} disabled={status === 'loading'} style={{ padding: '8px 12px', borderRadius: 12, border: '1px solid #ddd', background: '#fff' }}>Reload</button>
<div style={{ marginTop: 12, border: '1px solid #eee', borderRadius: 16, padding: 14 }}>
{status === 'idle' ? <div style={{ color: '#555' }}>Click reload.</div> : null}
{status === 'loading' ? <div>Loading...</div> : null}
{status === 'error' ? <div style={{ color: '#c1121f' }}>{error}</div> : null}
{status === 'success' ? (
<div>
<div><strong>{data.user}</strong></div>
<div style={{ color: '#555', marginTop: 6 }}>Streak: {data.streak} days</div>
</div>
) : null}
</div>
</div>
);
}
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