what is modal in react js code example

Example: react modal

import React from 'react';
import ReactDOM from 'react-dom';
import Modal from 'react-modal';
 
const customStyles = {
  content : {
    top                   : '50%',
    left                  : '50%',
    right                 : 'auto',
    bottom                : 'auto',
    marginRight           : '-50%',
    transform             : 'translate(-50%, -50%)'
  }
};
 
// Make sure to bind modal to your appElement (http://reactcommunity.org/react-modal/accessibility/)
Modal.setAppElement('#yourAppElement')
 
function App(){
  var subtitle;
  const [modalIsOpen,setIsOpen] = React.useState(false);
  function openModal() {
    setIsOpen(true);
  }