如何处理时间之间的时差

Question

I have jquery hours range picker and I am not using 'am' & 'pm' notation. I prefer 24h. I need to calculate the hours difference between selected hours.

User selects '09:00' & '12:00' -> 3 hours

My problem is with if he selects '20:00' & '00:00' -> must be 4 hours but gives negative. Alternatively; '23:00' & '02:00' -> negative

Should I take abs? or any other way?

Answer 1

You need to use modulo. Unfortunately Javascript's modulo is wrong.

 Number.prototype.mod = function(n) { return ((this % n) + n) % n; }; console.log((0 - 20).mod(24)); 

Answer 2

Simply add if check to the difference you get and if it's negative add 24 hours to it

var diff = function(a,b) {
  var difference = b - a;
  if (difference < 0) {
    return difference + 24;
  } else {
    return difference;
  }
}

Of course you will need to parse your time first. Here is a fiddle with alerts instead of returns. But this is the easiest way i guess, but mb not the best one fiddle