Interview question
What are Pure Components and when should you use them? Pure Components क्या हैं और कब use करें?
Answer
// Pure Component - automatically does shallow comparison of props/state
class PureCounter extends React.PureComponent {
render() {
return <h1>Count: {this.props.count}</h1>;
}
}
// Equivalent functional component with React.memo
const PureCounter = React.memo(({ count }) => {
return <h1>Count: {count}</h1>;
});
// When to use Pure Components:
// 1. Heavy rendering components
// 2. When props/state rarely change
// 3. Performance optimization
// Custom comparison
const Component = React.memo(
({ data }) => <div>{data.name}</div>,
(prevProps, nextProps) => {
return prevProps.data.id === nextProps.data.id;
}
);Pure Component:
- Automatically shallow comparison करता है
- Performance improve करता है
- PureComponent use करो या React.memo
Class:
class MyComponent extends React.PureComponent {}
Functional:
const Component = React.memo(() => {});Was this answer clear?