react-native中的以下组件：

import { useEffect, useState } from 'react'

let startValue = null // only using this to restart the counter from resetTimer() (other better approaches?)

export const NewTimer = () => {
  const [seconds, setSeconds] = useState(startValue)

  const formatedTime = () => {
    return [pad(parseInt(seconds / 60)), pad(seconds % 60)].join(':')
  }

  useEffect(() => {
    const timer = setInterval(() => setSeconds(++seconds), 1000) // I guess this line triggers the error
    return () => {
      clearInterval(timer)
    }
  }, [])

  return formatedTime
}

const pad = (num) => {
  return num.toString().length > 1 ? num : `0${num}`
}

export const resetTimer = () => {
  startValue = 0
}

导致未捕获的错误：“seconds”为只读
有谁能指出错误在哪里吗？谢谢！