useEffect hook in React
Returns a stateful value, and a function to update it
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>
  )
}
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