react hooks

const [state, setState] = useState(initialState);

import React, { useState } from 'react';

function Example() {
  // Declare a new state variable, which we'll call "count"  const [count, setCount] = useState(0);
  return (
    <div>
      <p>You clicked {count} times</p>
      <button onClick={() => setCount(count + 1)}>
        Click me
      </button>
    </div>
  );
}

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

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

import React, { useState, useEffect } from 'react';
function Example() {
  const [count, setCount] = useState(0);

  // Similar to componentDidMount and componentDidUpdate:  useEffect(() => {    // Update the document title using the browser API    document.title = `You clicked ${count} times`;  });
  return (
    <div>
      <p>You clicked {count} times</p>
      <button onClick={() => setCount(count + 1)}>
        Click me
      </button>
    </div>
  );
}

useEffect(() => {
  document.title = `You clicked ${count} times`;
}, [count]); // Only re-run the effect if count changes

componentDidUpdate(prevProps, prevState) {
  if (prevState.count !== this.state.count) {
    document.title = `You clicked ${this.state.count} times`;
  }
}

  useEffect(() => {
    document.title = `You clicked ${count} times`;
  });