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Start your free trialAlena Miadzvedskaya
6,386 PointsCan't stop the timer, it still ticks even after stop button was clicked
const Stopwatch = () => { const [isRunning, setIsRunning] = useState(false); const [elapsedTime, setElapsedTime] = useState(0); const [prevTime, setPrevTime] = useState(0);
const intervalID = () => { setInterval(() => tick(), 1000)}
const stopTimer = () => { clearInterval(intervalID) }
const handleStopwatch = () => { setIsRunning(!isRunning); if (!isRunning) { setPrevTime(Date.now()); } };
useEffect(() => { if(isRunning) { intervalID() } else { stopTimer() } }, [isRunning]);
const tick = () => { if (isRunning === true) { const now = Date.now(); const elapsedTimeNow = elapsedTime; const prevTimeNow = prevTime; setPrevTime(now); setElapsedTime(elapsedTimeNow + (now - prevTimeNow)); } };
const seconds = Math.floor(elapsedTime / 1000)
return ( <div className="stopwatch"> <h2>Stopwatch</h2> <span className="stopwatch-time">{ seconds }</span> <button onClick={handleStopwatch}>{isRunning ? "Stop" : "Start"}</button> <button>Reset</button> </div> ); };