Javascript：计算租约上的剩余时间（然后租用）（Rent Calculator）

Question

我在一家企业房地产机构工作，我正在创建一个内部页面供员工使用，其中将包含一些小工具供他们使用除其他事项外。

我一直试图放在一起的一件事是一个租金计算器，租赁计算器，从用户的租赁金额和租赁到期日期，需要确定剩余（从今天）的租赁时间和然后通知租赁剩余的租金是多少。

我找到了工作，主要是，但你可以看到它的相当长的（我假设在一定程度上它是），我感觉相当凌乱：

//calculates the remaining rent left to pay for terminated leases 
$("input[name='calcRent']").click(function() { 
    //gets rent and daily rent for later calculations 
    var rent = $("input[name='rentRent']").val(); 
    var dailyRate = (rent * 12)/365; 
    var leaseExpiry = $("input[name='leaseExpiry']").val(); 
    var remRent = $("input[name='remRent']"); 
    //breaks down lease expiry date and today's date into day, month, year parts 
    //so that units can be used in calculations 
    var ldd = leaseExpiry.substr(0,2); 
     ldd = parseInt(ldd, 10); 
    var lmm = leaseExpiry.substr(3,2); 
     lmm = parseInt(lmm, 10); 
    var lyyyy = leaseExpiry.substr(6,4); 
     lyyyy = parseInt(lyyyy, 10); 
    var date = new Date(); 
    var tdd = date.getDate(); 
    var tmm = date.getMonth()+1; 
    var tyyyy = date.getFullYear(); 
     //if the expiry month is next year (or later) add 12 to expiry 
     //month value to make "lmm - tmm" calculation give positive value 
     if (lyyyy > tyyyy) { 
      lmm += (12 * (lyyyy - tyyyy)); 
     } 
    //takes the current month from the expiry month to get the number of 
    //whole months left in the lease, then checks day values to see whether 
    //we have already passed the rent due date for this month (and so there's 
    //one less whole month left than we originally thought), taking 1 from 
    //wholeMths value if so 
    var wholeMths = lmm - tmm; 
     if (ldd == (tdd - 1)) { 
      wholeMths = wholeMths; 
     } else if (ldd < (tdd - 1)) { 
      wholeMths -= 1; 
     } 
    //works out if there are any days to be charged at daily rate (i.e. not 
    //part of a whole month). If today's date(tdd) == expiry date(ldd)+1 we have no 
    //leftover days (rental month runs like so: 12/04 - 11/05). If tdd > ldd+1 
    //(leftover days cross over a month end) we set checkMonth to true so the following 
    //if statement runs 
    var checkMonth = false; 
    var daysLeft = 0; 
     if (tdd == (ldd + 1)) { 
      daysLeft = 0; 
     } else if (tdd > ldd + 1) { 
      daysLeft = (31 - tdd) + ldd; 
      checkMonth = true; 
     } else { 
      daysLeft = ldd - tdd; 
     } 
     //as per the above line: "daysLeft = (31 - tdd) + ldd;" we assume months have 31 days 
     //as the majority do, this if checks whether the month end that we cross over with our 
     //leftover days actually has 30 days, if not we check whether it's February and whether 
     //it's a leap year so that we get the appropriate no. of days to charge for - if it meets 
     //any of these criteria the relevant no. of days are subtracted from daysLeft 
     if ((lmm == 05 || lmm == 07 || lmm == 10 || lmm == 12 
      || lmm == 17 || lmm == 19 || lmm == 22 || lmm == 24) && checkMonth) { 
      daysLeft -= 1; 
     } else if ((lmm == 03 || lmm == 15) && checkMonth) { 
      if (lyyyy % 4 == 0) { 
       daysLeft -= 2; 
      } else { 
       daysLeft -= 3; 
      } 
     } 
     checkMonth = false; 
    var balance = (wholeMths * rent) + (daysLeft * dailyRate); 

    remRent.val(balance.toFixed(2));   
}); 

之一特别让我感到困扰的是在下一年出现租约到期的地方。我还没有弄清楚如何整理那个月的'价值'（正如你可以在最后看到的那样）。

对此的任何建议将不胜感激，因为评论的数量和数量似乎与实际代码有些不成比例 - 但我认为目前它们是必要的，因为它不太清楚发生了什么。

感谢，

Answer 1

对你做了什么，但你需要好好把握好工作的内置可在JavaScript中使用Date类日期计算。

具体获得的天数之间的约会，你可以使用下面的逻辑：

var currentDate = new Date(); // This will get today's date 
currentDate.setHours(0,0,0,0); // Remove time from consideration 
           // As recommended by @NickSlash 

// The following get's the lease expiration date using the year, 
// month and date that you have already extracted from the input 
var leaseExpirationDate = new Date(lyyyy, lmm, ldd); 

// The number of days remaining in the lease is simply the following: 
var one_day = 1000*60*60*24; 
var daysLeftInLease = (leaseExpirationDate - currentDate)/one_day; 

这片神奇的是因为内部的Date类保持日期值1/1/1970以来的毫秒数。因此，如果你减去两个Date对象，你会得到它们之间的毫秒数。然后，您可以简单地将该值除以一天中的毫秒数，以获取日期之间的天数。