问题[localstorage]

有一个代码

let doVibro = false;

document.getElementById("vibro_on").addEventListener('click', () => {
  doVibro = true;
});

document.getElementById("vibro_off").addEventListener('click', () => {
  doVibro = false;
});

document.getElementById("do-vibro").addEventListener('click', () => {
  doVibro ? navigator.vibrate([50]) : navigator.vibrate([0]);
});
<button id="vibro_on">ON</button>
<button id="vibro_off">OFF</button>

<button onclick="vibro()" id="do-vibro">TEST</button>

需要在重新加载页面时，通过按TESET保持振动，即设备记住是否振动，然后在重新加载页面后保持振动。

如何将本地存储中的计时器值减一？使用了“useLocalStorage”钩子，但该值不会动态减一

计时器本身：

    const [timeLeft, setTimeLeft] = useLocalStorage('timer',  5 * 60)

    const getPadTime = (time) => time.toString().padStart(2, '0')

    const minutes = getPadTime(Math.floor(timeLeft / 60))
    const seconds = getPadTime(timeLeft - minutes * 60)

    useEffect(() => {
        const interval = setInterval(() => {
            setTimeLeft((timeLeft) => (timeLeft >= 1 ? timeLeft - 1 : setDisabled() ||  5 * 60))
        }, 1000)
        return () => clearInterval(interval) 
    }, [])

'useLocalStorage' 挂钩数据：

import {useState} from 'react'

function useLocalStorage(key, initialValue) {
    // State to store our value
    // Pass initial state function to useState so logic is only executed once
    const [storedValue, setStoredValue] = useState(() => {
      if (typeof window === "undefined") {
        return initialValue;
      }
  
      try {
        // Get from local storage by key
        const item = window.localStorage.getItem(key);
        // Parse stored json or if none return initialValue
        return item ? JSON.parse(item) : initialValue;
      } catch (error) {
        // If error also return initialValue
        console.log(error);
        return initialValue;
      }
    });
  
    // Return a wrapped version of useState's setter function that ...
    // ... persists the new value to localStorage.
    const setValue = (value) => {
      try {
        // Allow value to be a function so we have same API as useState
        const valueToStore =
          value instanceof Function ? value(storedValue) : value;
        // Save state
        setStoredValue(valueToStore);
        // Save to local storage
        if (typeof window !== "undefined") {
          window.localStorage.setItem(key, JSON.stringify(valueToStore));
        }
      } catch (error) {
        // A more advanced implementation would handle the error case
        console.log(error);
      }
    };
  
    return [storedValue, setValue];
  }

  export default useLocalStorage

你好，我刚开始学习js。

window.localStorage.getItem()并window.sessionStorage.getItem()返回null，尽管如果您在 chrome 中使用应用程序，则存在值 \u200b\u200bare。

let startBtn = document.getElementById("startBtn")
startBtn.onclick = game;
document.getElementById('clearBR').addEventListener('click', ClearBestResult)
document.getElementById('clearBRforAllTime').addEventListener('click', ClearBestResultForAllTime)
let result
function game() {
   let count = 0
   const nickname = document.getElementById("nickname").value
   document.getElementById('click').addEventListener('click', clickCount)
   let arr = []
   function clickCount() {
      count++
      arr.push(count)
   }
   try {
      if (nickname === "") throw new Error()
   } catch (e) {
      alert('nickname is empty')
   }
   finally {
      setTimeout(function () {
         result = arr.length
         alert(`You clicked ${result} times`)
         if (sessionStorage.getItem, (nickname, result) < result || sessionStorage.getItem, (nickname, result) === undefined) {
            sessionStorage.clear()
            sessionStorage.setItem(nickname, result.toString())
         } else if (result > localStorage.getItem, (nickname, result) || localStorage.getItem === undefined) {
            localStorage.clear()
            localStorage.setItem(nickname, result.toString())
         }
         count = 0
         arr.splice(0, arr.length);
      }, 5000);
   }
   document.getElementById('BRforAllTime').addEventListener('click', bestForAllTimes)
   document.getElementById('BR').addEventListener('click', bestResult)
   function bestForAllTimes() {
      alert(`Best result for the whole time is: ${localStorage.getItem(result)} by ${localStorage.getItem("nickname")}`)
   }
   function bestResult() {
      alert(`Best result is ${window.sessionStorage.getItem(result)}`)
   }
   console.log(sessionStorage.getItem(result)) // null
   console.log(localStorage.getItem(result)) //null
}
function ClearBestResult() {
   window.sessionStorage.clear()
   alert('Best result is cleared')
}
function ClearBestResultForAllTime() {
   localStorage.clear()
   alert('Best result for the whole time is cleared')
}