返回未来日期 - Javascript（年，月，日）

Question

I have been trying to work this challenge for a while. It is finally working with a past date, it gives me the format that I want (year, month, days), but is not working with future dates. How can I rework this example, so it will also work with future dates? as of now I get an empty string.

 function reworkedInBetweenDays(year, month, day) { var today = new Date(); var fromdate = new Date(year, month - 1, day); var yearsDiff = today.getFullYear() - fromdate.getFullYear(); var monthsDiff = today.getMonth() - fromdate.getMonth(); var daysDiff = today.getDate() - fromdate.getDate(); if (monthsDiff < 0 || (monthsDiff === 0 && daysDiff < 0)) yearsDiff--; if (monthsDiff < 0) monthsDiff += 12; if (daysDiff < 0) { var fromDateAux = fromdate.getDate(); fromdate.setMonth(fromdate.getMonth() + 1, 0); daysDiff = fromdate.getDate() - fromDateAux + today.getDate(); monthsDiff--; } var result = []; if (yearsDiff > 0) result.push(yearsDiff + (yearsDiff > 1 ? " years" : " year")); if (monthsDiff > 0) result.push(monthsDiff + (monthsDiff > 1 ? " months" : " month")); if (daysDiff > 0) result.push(daysDiff + (daysDiff > 1 ? " days" : " day")); return result.join(', '); } console.log(reworkedInBetweenDays(2013, 4, 8)); console.log(reworkedInBetweenDays(2014, 1, 16)); console.log(reworkedInBetweenDays(2016, 1, 31)); console.log(reworkedInBetweenDays(2017, 2, 16)); 

Answer 1

You just need to use Math.abs() to getting your yearsDiff

function reworkedInBetweenDays(year, month, day) {

   var today = new Date();

   var fromdate = new Date(year, month - 1, day);

   var yearsDiff = Math.abs(today.getFullYear() - fromdate.getFullYear()); //HERE
   var monthsDiff = today.getMonth() - fromdate.getMonth();
   var daysDiff = today.getDate() - fromdate.getDate();

   if (monthsDiff < 0 || (monthsDiff === 0 && daysDiff < 0))
      yearsDiff--;
   if (monthsDiff < 0)
      monthsDiff += 12;

   if (daysDiff < 0) {
      var fromDateAux = fromdate.getDate();
      fromdate.setMonth(fromdate.getMonth() + 1, 0);
      daysDiff = fromdate.getDate() - fromDateAux + today.getDate();
      monthsDiff--;
   }

   var result = [];

   if (yearsDiff > 0)
      result.push(yearsDiff + (yearsDiff > 1 ? " years" : " year"));
   if (monthsDiff > 0)
      result.push(monthsDiff + (monthsDiff > 1 ? " months" : " month"));
   if (daysDiff > 0)
      result.push(daysDiff + (daysDiff > 1 ? " days" : " day"));

   return result.join(', ');

}

console.log(reworkedInBetweenDays(2013, 4, 8));
console.log(reworkedInBetweenDays(2014, 1, 16));
console.log(reworkedInBetweenDays(2016, 1, 31));
console.log(reworkedInBetweenDays(2017, 2, 16));

Answer 2

It works adding this code at the end

if (yearsDiff < 0)
  result.push(yearsDiff*(-1) + (yearsDiff*(-1) > 1 ? " years in the future" : " year in the future"));
if (monthsDiff < 0)
  result.push(monthsDiff*(-1) + (monthsDiff*(-1) > 1 ? " months in the future" : " month in the future"));
if (daysDiff < 0)
  result.push(daysDiff*(-1) + (daysDiff*(-1) > 1 ? " days in the future" : " day  in the future"));

Answer 3

monthsDiff and daysDiff are both zero and yearsDiff is -1, meaning none of them set off the if statements at the bottom. You need to add some code to handle when all these values are zero or negative.