useClock

语法

---

定义 hook

import React, {useState, useEffect} from 'react';

const useClock = () => {
    const [time, setTime] = useState<Date>(new Date());

    useEffect(() => {
        const timer = setInterval(() => {
            setTime(new Date());
        }, 1000);
        return () => {
            clearInterval(timer);
        };
    }, []);

    return time;
};

export default useClock;

使用 hook

import React from 'react';
import useClock from './hooks/useClock';

function App() {
    const time = useClock();
    return (
        <div>
            <div>现在时间为: {time.toLocaleDateString()}</div>
        </div>
    );
}

export default App;