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javascript - 如何使用 react 钩子(Hook)重置 setInterval 函数

转载 作者:行者123 更新时间:2023-12-05 01:15:05 25 4
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我正在使用 useInterval 钩子(Hook),由 here 中的 Dan Abramov 编写

如何重置计数器?例如点击按钮?

代码在 codesandbox

function Counter() {
const [count, setCount] = useState(0);

useInterval(() => {
// Your custom logic here
setCount(count + 1);
}, 1000);

const resetInterval = () => {};

return (
<>
<h1>{count}</h1>
<button ocClick={resetInterval}>Reset</button>
</>
);
}

最佳答案

要重置计数器,请从 resetInterval 调用 setCount(0):

注意:您在按钮上拼错了 onClick

function Counter() {
const [count, setCount] = useState(0);

useInterval(() => {
// Your custom logic here
setCount(count => count + 1);
}, 1000);

const resetInterval = () => setCount(0);

return (
<>
<h1>{count}</h1>
<button onClick={resetInterval}>Reset</button>
</>
);
}

要停止/恢复间隔,您可以重构 useInterval 以返回 toggleRunning 函数和当前 running 状态。

function useInterval(callback, delay) {
const savedCallback = useRef();
const intervalId = useRef(null);
const [currentDelay, setDelay] = useState(delay);

const toggleRunning = useCallback(
() => setDelay(currentDelay => (currentDelay === null ? delay : null)),
[delay]
);

const clear = useCallback(() => clearInterval(intervalId.current), []);

// Remember the latest function.
useEffect(() => {
savedCallback.current = callback;
}, [callback]);

// Set up the interval.
useEffect(() => {
function tick() {
savedCallback.current();
}

if (intervalId.current) clear();

if (currentDelay !== null) {
intervalId.current = setInterval(tick, currentDelay);
}

return clear;
}, [currentDelay, clear]);

return [toggleRunning, !!currentDelay];
}

重置和暂停/恢复的工作示例 (Sandbox)

const { useState, useEffect, useRef, useCallback, Fragment } = React;

function Counter() {
const [count, setCount] = useState(0);

const [toggle, running] = useInterval(() => {
// Your custom logic here
setCount(count => count + 1);
}, 100);

const resetCounter = () => setCount(0);

return (
<Fragment>
<h1>{count}</h1>
<button onClick={resetCounter}>Reset</button>
<button onClick={toggle}>{running ? "Pause" : "Resume"}</button>
</Fragment>
);
}

function useInterval(callback, delay) {
const savedCallback = useRef();
const intervalId = useRef(null);
const [currentDelay, setDelay] = useState(delay);

const toggleRunning = useCallback(
() => setDelay(currentDelay => (currentDelay === null ? delay : null)),
[delay]
);

const clear = useCallback(() => clearInterval(intervalId.current), []);

// Remember the latest function.
useEffect(() => {
savedCallback.current = callback;
}, [callback]);

// Set up the interval.
useEffect(() => {
function tick() {
savedCallback.current();
}

if (intervalId.current) clear();

if (currentDelay !== null) {
intervalId.current = setInterval(tick, currentDelay);
}

return clear;
}, [currentDelay, clear]);

return [toggleRunning, !!currentDelay];
}

ReactDOM.render(<Counter />, root);
<script crossorigin src="https://unpkg.com/react@16/umd/react.development.js"></script>
<script crossorigin src="https://unpkg.com/react-dom@16/umd/react-dom.development.js"></script>

<div id="root"></div>

关于javascript - 如何使用 react 钩子(Hook)重置 setInterval 函数,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/56952038/

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