State in a functional components

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

...

function App() {

  const[greeting, setGreeting] = useState('hello');

  useEffect(() => {

    setTimeout(() => {

      setGreeting('hello again!')

    }, 5000)

  });

...

  return(

    <div className="App">

      {greeting}

      {movies.map((movie,index) => {

...