重复函数调用后时间间隔不变

Question

我的代码的目标是每5秒调用一次函数，它成功完成。问题是，当我每次都声明我的秒变量时，即使开始日期不应该改变，它也不会改变。

func timedUpdate()
{

    let initialBank = 2000
    let dateOfInstallation = UserDefaults.standard.object(forKey: "installDate")
    let seconds = date.timeIntervalSince(dateOfInstallation as! Date) / 8.64

    let bestStreak = (UserDefaults.standard.integer(forKey: "bestStreak"))
    let days = seconds / 86400


    print(seconds/8.64)
    print(UserDefaults.standard.object(forKey: "bestStreak")!)

    if (Int(days) > bestStreak)
    {
        UserDefaults.standard.set(days, forKey: "bestStreak")
    }

    bestStreakLabel.text = "\(Int(bestStreak)) Days"
    currentStreakLabel.text = "\(Int(days)) Days"
    currentStreakBar.progress = CGFloat(Float(days)/Float(bestStreak))
    bestStreakBar.progress = 1

    getTodaysSteps { [weak self] steps in
        self?.bankTotalLabel.text = "\(Int(steps) - Int(seconds/8.64) + Int(initialBank))"
        self?.circleLabel.progress = Double(((Double(steps) - Double(seconds) + Double(initialBank))) / 10000)

        if (Int(steps) - Int(seconds) + Int(initialBank) < 0)
        {
            // Will Eventually need a popup screen here to say you lost and streak is reset to 0
            self?.resetApp()
        }
    }
}

当我打印秒的值时，它始终是相同的小数，非常接近0.请提前感谢您的帮助！