useEffect in React Hooks

useEffect.js

import React, { useState, useEffect } from 'react';

function App() {
  const [count, setCount] = useState(0)

  useEffect(() => {
    document.title = `You clicked ${count} times`
    console.log('component did mount')
  }, []); // componentDidMount, only when the component has been rendered at start

  useEffect(() => {
    document.title = `You clicked ${count} times`
    console.log('component did update')
  }, [count]) // Now this function is dependent on the value being passed

  return (
    <div className="App">
      <button onClick={() => setCount(count + 1)}>Increase Count</button>
    </div>
  );
}

export default App;