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import React, { useState, useEffect } from 'react';
import styled from 'styled-components';
const Timer = () => {
const SPACE = 32
const [time, setTime] = useState("00:00:00")
const [stopwatchStarted, setStopwatchStarted] = useState(false);
const [timer, setTimer] = useState(0);
let startingTime;
const handleKeyPress = event => {
if (event.keyCode === SPACE){
if (!stopwatchStarted) {
startingTime = Date.now();
setStopwatchStarted(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)
setStopwatchStarted(false);
startingTime = 0;
return false;
}
}
}
useEffect(() => {
window.addEventListener("keypress", handleKeyPress);
return () => {
window.removeEventListener("keypress", handleKeyPress);
};
})
return (
<Root>
<span>{time}</ span>
</Root>
);
}
const Root = styled.div`
background-color: skyblue;
padding: 8px;
display: inline-block;
font-size: 32px;
color: pink;
`;
export default Timer;
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