import React, { useState, useEffect } from 'react'; import styled from 'styled-components'; import {post} from '../../requests'; const Timer = () => { const SPACE = 32 const [time, setTime] = useState("00:00:00") const [running, setRunning] = useState(false); const [timer, setTimer] = useState(0); let startingTime; const handleKeyUp = event => { if (event.keyCode === SPACE){ if (!running) { startingTime = Date.now(); setRunning(true); setTimer(setInterval(() => setTime(() => { const timeGap = Math.floor((Date.now() - startingTime) / 10); let resultTime = ""; const minute = Math.floor(timeGap / 6000); if (minute < 10) resultTime += '0'; resultTime += minute + ':'; let second = Math.floor(timeGap / 100); if (second < 10) resultTime += '0'; if (second > 59) second %= 60 resultTime += second + ':'; const mill = timeGap % 100; if (mill < 10) resultTime += '0'; resultTime += mill; return resultTime; }), 10)) } else { clearInterval(timer); setRunning(false); startingTime = 0; post('solutions/', {result: time}); return false; } } } useEffect(() => { window.addEventListener("keyup", handleKeyUp); return () => { window.removeEventListener("keyup", handleKeyUp); }; }) return ( {time} ); } const Root = styled.div` background-color: skyblue; padding: 8px; display: inline-block; font-size: 32px; color: pink; `; export default Timer;