javascript - setDate() 意外累积天数

Question

使用 Google 表格。我正在尝试检查工作表中更改日期后两周内的数据条目。所以我需要一个可变日期，设置为输入日期后 1、2、3...14 天。

var startFortnightDate = ss.getSheetByName('FortnightValidation').getRange('C3').setValue("=to_date("+e.value+")").getValue();
var variableDate = startFortnightDate;
//Loop start
for (var dayCount = 1; dayCount < 8; dayCount++) {//each day of the week
  for (var weekCount = 0; weekCount < 2; weekCount++) {//each week of the fortnight
variableDate = startFortnightDate;//this is to reset the date to allow setting of the date to variable number of days forward
variableDate.setDate(variableDate.getDate() + (dayCount + (7*weekCount)));//This changes the date and accumulates if it isn't reset????
Logger.log("Line 197. variableDate = " + variableDate);
Logger.log("Line 199 " + startFortnightDate);
}
}
//Loop end

由于我无法理解的原因，即使我在每个循环中进行重置，fortnightStartDate 似乎也在累积以及variableDate。是否将 startFortnightDate 的值以外的值分配给了 variableDate？

部分日志如下:

[16-08-08 16:01:43:609 AEST] Line 199 Mon Feb 13 2389 00:00:00 GMT+1100 (AEDT)
[16-08-08 16:01:43:609 AEST] Line 197. variableDate = Mon Feb 27 2389 00:00:00 GMT+1100 (AEDT)
[16-08-08 16:01:43:610 AEST] Line 199 Mon Feb 27 2389 00:00:00 GMT+1100 (AEDT)
[16-08-08 16:01:43:610 AEST] Line 197. variableDate = Tue Feb 28 2389 00:00:00 GMT+1100 (AEDT)
[16-08-08 16:01:43:611 AEST] Line 199 Tue Feb 28 2389 00:00:00 GMT+1100 (AEDT)
[16-08-08 16:01:43:611 AEST] Line 197. variableDate = Wed Mar 08 2389 00:00:00 GMT+1000 (AEST)
[16-08-08 16:01:43:611 AEST] Line 199 Wed Mar 08 2389 00:00:00 GMT+1000 (AEST)
[16-08-08 16:01:43:612 AEST] Line 197. variableDate = Fri Mar 10 2389 00:00:00 GMT+1000 

Answer 1

您可能遇到指针问题，但我不确定。这是对我有用的:

var startFortnightDate = ss.getSheetByName('FortnightValidation').getRange('C3').setValue("=to_date("+e.value+")").getValue(); 
  //var startFortnightDate = new Date();  // Used for testing since I don't have your spreadsheet
  startFortnightDate = Date.parse(startFortnightDate); // Convert date object to milliseconds 
  var variableDate = startFortnightDate;
  var inc = 24*60*60*1000;               // One day in milliseconds
  for (var weekCount = 0; weekCount<2; weekCount++){
    for (var dayCount = 1; dayCount<8; dayCount++){
      variableDate += inc;              // Add one day
      Logger.log('startFortnightDate = %s',new Date(startFortnightDate))
      Logger.log('variableDate = %s',new Date(variableDate))
    }
  }

您会注意到我改变了循环的顺序。按照你的方式，你增加两周，然后增加一天，而不是两周增加一天。

我还通过使用 Date.parse(dateObject) 转换为毫秒来简化了它，这对我来说是一种更简单的操作日期的方法。然后，在每个循环中，variableDate 增加一天，但 startFortnightDate 保持原样。为了显示，使用new Date(milliseconds)转换回日期对象。 w3schools 的日期对象引用非常全面，多次帮助了我:

http://www.w3schools.com/jsref/jsref_obj_date.asp

这是我的日志的一部分:

[16-08-08 03:00:08:361 EDT] startFortnightDate = Mon Aug 08 03:00:08 GMT-04:00 2016
[16-08-08 03:00:08:362 EDT] variableDate = Tue Aug 09 03:00:08 GMT-04:00 2016
[16-08-08 03:00:08:363 EDT] startFortnightDate = Mon Aug 08 03:00:08 GMT-04:00 2016
[16-08-08 03:00:08:363 EDT] variableDate = Wed Aug 10 03:00:08 GMT-04:00 2016
[16-08-08 03:00:08:364 EDT] startFortnightDate = Mon Aug 08 03:00:08 GMT-04:00 2016
[16-08-08 03:00:08:365 EDT] variableDate = Thu Aug 11 03:00:08 GMT-04:00 2016
[16-08-08 03:00:08:365 EDT] startFortnightDate = Mon Aug 08 03:00:08 GMT-04:00 2016
[16-08-08 03:00:08:366 EDT] variableDate = Fri Aug 12 03:00:08 GMT-04:00 2016
[16-08-08 03:00:08:367 EDT] startFortnightDate = Mon Aug 08 03:00:08 GMT-04:00 2016
[16-08-08 03:00:08:367 EDT] variableDate = Sat Aug 13 03:00:08 GMT-04:00 2016