javascript - 如何在 React JS 中实时显示时间和日期？

Question

简报:
嗨，我创建了一个 Hook useDate()显示当前时间和日期，如下所示:

interface ReturnDate {
  time: string;
  date: string;
  wish: string;
}

export const useDate = (): ReturnDate => {
  const locale = 'en';
  const today = new Date();

  const day = today.toLocaleDateString(locale, { weekday: 'long' });
  const date = `${day}, ${today.getDate()} ${today.toLocaleDateString(locale, { month: 'long' })}\n\n`;

  const hour = today.getHours();
  const wish = `Good ${(hour < 12 && 'Morning') || (hour < 17 && 'Afternoon') || 'Evening'}, `;

  const time = today.toLocaleTimeString(locale, { hour: 'numeric', hour12: true, minute: 'numeric' });

  return {
    date,
    time,
    wish,
  };
};

我在我的 中使用它组件 如下:

const ProfileGreetings: FC = () => {
  const { firstName } = useUserDetails();
  const { date, time, wish } = useDate();

  return (
    <div className="greetings-container">
      <h1>
        {wish}
        <PrimaryText text={`${firstName || ''}!`} />
      </h1>

      <div>
        <h3>
          {date}
          <br />
          {time}
        </h3>
      </div>
    </div>
  );
};

应用程序中的日期/时间格式:
8 月 2 日，星期日
晚上 11:54
问题陈述:
目前发生的情况是日期和时间直到我 才更新。刷新 这页纸。有什么方法可以在 中更新以下所有内容实时 ?
我正在考虑使用 每 1 分钟后的间隔 计算更新的时间和日期，但不知道这是否是个好主意。我也不知道如何开始，间隔将如何 清除 ?
谢谢! :)

Answer 1

由于您可以在自定义 Hook 中使用 Hook ，因此您可以创建一个间隔来更新每分钟，如下所示:

export const useDate = () => {
  const locale = 'en';
  const [today, setDate] = React.useState(new Date()); // Save the current date to be able to trigger an update

  React.useEffect(() => {
      const timer = setInterval(() => { // Creates an interval which will update the current data every minute
      // This will trigger a rerender every component that uses the useDate hook.
      setDate(new Date());
    }, 60 * 1000);
    return () => {
      clearInterval(timer); // Return a funtion to clear the timer so that it will stop being called on unmount
    }
  }, []);

  const day = today.toLocaleDateString(locale, { weekday: 'long' });
  const date = `${day}, ${today.getDate()} ${today.toLocaleDateString(locale, { month: 'long' })}\n\n`;

  const hour = today.getHours();
  const wish = `Good ${(hour < 12 && 'Morning') || (hour < 17 && 'Afternoon') || 'Evening'}, `;

  const time = today.toLocaleTimeString(locale, { hour: 'numeric', hour12: true, minute: 'numeric' });

  return {
    date,
    time,
    wish,
  };
};