Usestate React
import React , { useState } from 'react' ; export default function QuizNavBar ({ questions }) { const [ questionIndex , setQuestionIndex ] = useState ( 0 ); const goBack = () => setQuestionIndex (( prevQuestionIndex ) => prevQuestionIndex - 1 ); const goToNext = () => setQuestionIndex (( prevQuestionIndex ) => prevQuestionIndex + 1 ); const onFirstQuestion = questionIndex === 0 ; const onLastQuestion = questionIndex === questions . length - 1 ; return ( <nav> <span> Question # { questionIndex + 1 }...