延时后启动间隔，按钮释放/反应时停止

Question

我试图在React中建立一个简单的加/减控制。当点击加号或减号时(由onMouseDown触发)，该值应通过定义的步骤改变，当按钮保持时，该值应在指定的延迟后以指定的间隔-/减少。当按钮释放(onMouseUp)时，间隔应停止。

下面的代码运行在onMouseDown和保持，但当我只是点击按钮的间隔开始无论如何。我看到我需要确保按钮在间隔开始前仍然处于下，但我如何实现这一点?谢谢你的建议。

let plusTimer = useRef(null);
const increment = () => {
setMyValue(prev => prev + myStep);
setTimeout(() => {
plusTimer.current = setInterval(
() => setMyValue(prev => prev + myStep),
100
);
}, 500);
};
const intervalClear = () => {
clearInterval(plusTimer.current);
};

Answer 1

我想我会让代码自己说话:

const {useCallback, useEffect, useState} = React;
const CASCADE_DELAY_MS = 1000;
const CASCADE_INTERVAL_MS = 100;
function useDelayedCascadeUpdate(intervalTime, delay, step, callback) {
const [started, setStarted] = useState(false);
const [running, setRunning] = useState(false);
const update = useCallback(() => callback((count) => count + step), [
callback,
step
]);
const handler = useCallback(() => {
update();
setStarted(true);
}, [update, setStarted]);
const reset = useCallback(() => {
setStarted(false);
setRunning(false);
}, [setStarted, setRunning]);
useEffect(() => {
if (started) {
const handler = setTimeout(() => setRunning(true), delay);
return () => {
clearTimeout(handler);
};
}
}, [started, setRunning, delay]);
useEffect(() => {
if (running) {
const handler = setInterval(update, intervalTime);
return () => {
clearInterval(handler);
};
}
}, [running, update, intervalTime]);
return [handler, reset];
}
function App() {
const [count, setCount] = useState(0);
const [incrementHandler, incrementReset] = useDelayedCascadeUpdate(
CASCADE_INTERVAL_MS,
CASCADE_DELAY_MS,
1,
setCount
);
const [decrementHandler, decrementReset] = useDelayedCascadeUpdate(
CASCADE_INTERVAL_MS,
CASCADE_DELAY_MS,
-1,
setCount
);
return (
<div>
<div>{count}</div>
<button onMouseDown={incrementHandler} onMouseUp={incrementReset}>
+
</button>
<button onMouseDown={decrementHandler} onMouseUp={decrementReset}>
-
</button>
</div>
);
}
ReactDOM.render(<App />, document.body);

<script src="https://cdnjs.cloudflare.com/ajax/libs/react/17.0.1/umd/react.production.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react-dom/17.0.1/umd/react-dom.production.min.js"></script>