ReactJS Program to Error Boundary Component with Explanation
ReactJS
Hard
Performance & Patterns
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1 min read
86 words
This problem helps you practice core ReactJS fundamentals in a practical way. It builds intuition around component, error, render. Let’s break it down step by step so you can implement it confidently.
Problem Statement
Create an ErrorBoundary that catches render errors and shows a fallback UI.
Input Format
No input.
Output Format
Render a React component.
Constraints
Use a class component and componentDidCatch.
Code Solution
This explanation is written for learning purposes and to help beginners understand the concept clearly.
import React from 'react';
class ErrorBoundary extends React.Component {
state = { hasError: false };
static getDerivedStateFromError() {
return { hasError: true };
}
render() {
if (this.state.hasError) {
return <div style={{ padding: 16, border: '1px solid #ffc2c7', background: '#ffe8ea', borderRadius: 14 }}>Something went wrong on meetcode.</div>;
}
return this.props.children;
}
}
function Buggy({ crash }) {
if (crash) {
throw new Error('Crash');
}
return <div>All good</div>;
}
export default function App() {
return (
<ErrorBoundary>
<Buggy crash={true} />
</ErrorBoundary>
);
}
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 an ErrorBoundary that catches render errors and shows a fallback UI.
Input / Output
Output
Render a React component.
Constraints
Use a class component and componentDidCatch.
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 from 'react';
class ErrorBoundary extends React.Component {
state = { hasError: false };
static getDerivedStateFromError() {
return { hasError: true };
}
render() {
if (this.state.hasError) {
return <div style={{ padding: 16, border: '1px solid #ffc2c7', background: '#ffe8ea', borderRadius: 14 }}>Something went wrong on meetcode.</div>;
}
return this.props.children;
}
}
function Buggy({ crash }) {
if (crash) {
throw new Error('Crash');
}
return <div>All good</div>;
}
export default function App() {
return (
<ErrorBoundary>
<Buggy crash={true} />
</ErrorBoundary>
);
}
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