Answers for "react use hooks in class component"

equivalent class, hooks and function components

class Example extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      count: 0
    };
  }

  render() {
    return (
      <div>
        <p>You clicked {this.state.count} times</p>
        <button onClick={() => this.setState({ count: this.state.count + 1 })}>
          Click me
        </button>
      </div>
    );
  }
}

react hooks inside class component

import { useEffect, useState } from 'react';

export function useScreenWidth(): number {
  const [width, setWidth] = useState(window.innerWidth);

  useEffect(() => {
    const handler = (event: any) => {
      setWidth(event.target.innerWidth);
    };

    window.addEventListener('resize', handler);

    return () => {
      window.removeEventListener('resize', handler);
    };
  }, []);

  return width;
}