text: import { useEffect, useRef, useCallback } from 'react'
  
  export default function Index() {
    const workerRef = useRef()
    useEffect(() => {
      workerRef.current = new Worker(new URL('../worker.js', import.meta.url))
      workerRef.current.onmessage = (evt) =>
        alert(`WebWorker Response => ${evt.data}`)
      return () => {
        workerRef.current.terminate()
      }
    }, [])
  
    const handleWork = useCallback(async () => {
      workerRef.current.postMessage(100000)
    }, [])
  
    return (
      <div>
        <p>Do work in a WebWorker!</p>
        <button onClick={handleWork}>Calculate PI</button>
      </div>
    )
  }
  