Compare two time (hh:mm:ss) strings

Question

I have two time strings in hh:mm:ss format. (eg: 12:40:13 and 20:01:01.) How can I compare these in JavaScript?

Answer 1

DEMO HERE

I prefer to have date objects, but as pointed out elsewhere, you can just convert to seconds if you want to do simple compares

function dateCompare(time1,time2) {
  var t1 = new Date();
  var parts = time1.split(":");
  t1.setHours(parts[0],parts[1],parts[2],0);
  var t2 = new Date();
  parts = time2.split(":");
  t2.setHours(parts[0],parts[1],parts[2],0);

  // returns 1 if greater, -1 if less and 0 if the same
  if (t1.getTime()>t2.getTime()) return 1;
  if (t1.getTime()<t2.getTime()) return -1;
  return 0;
}

alert(dateCompare("12:40:13","20:01:01"));

For seconds:

function dateDiff(time1,time2) {
  var t1 = new Date();
  var parts = time1.split(":");
  t1.setHours(parts[0],parts[1],parts[2],0);
  var t2 = new Date();
  parts = time2.split(":");
  t2.setHours(parts[0],parts[1],parts[2],0);

  return parseInt(Math.abs(t1.getTime()-t2.getTime())/1000);
}

Assuming you have 24 hour times and same padding you can do simple string compare

 var t1 = "12:40:13", t2= "20:01:01";
 if (t1<t2) {
    console.log(t1," is < ", t2);
 }

Answer 2

Here's another take:

function compareTimes(timeOne, timeTwo) {           
    if(daterize(timeOne) > daterize(timeTwo)) return 1;
    if(daterize(timeOne) < daterize(timeTwo)) return -1;
    return 0;
}

function daterize(time) {
    return Date.parse("Thu, 01 Jan 1970 " + time + " GMT");
}

You may also want to take a look at the MDN Javascript docs for Dates. Javascript comes with a lot of gotchas, like Date.month going from 0-11.

Answer 3

Here is one suggestion that I modified from the solution in this website here, hope it helps.

function compareTime(time_1, time_2) {
   var s1 = 
       time1.split(":")[0] * 3600 + time1.split(":")[1] * 60 + time1.split(":")[2];
   var s2 = 
       time2.split(":")[0] * 3600 + time2.split(":")[1] * 60 + time1.split(":")[2];
   return Math.abs(s1 - s2); // Gets difference in seconds
}

var time_1 = "12:40:13", time_2 = "20:01:01";
document.write(compareTime(time_1, time_2));

Answer 4

 Date.parse('01/01/2011 10:20:45') > Date.parse('01/01/2011 5:10:10')

 The 1st January is an arbitrary date, doesn't mean anything.

Answer 5

If "compare" means "see if they are equal", and the two have the same format, why not simply:

var time1 = "12:40:13";
var time2 = "20:01:01";

if (time1 == time2) {
    // do stuff
}

If you need to get the difference in time, the conversion to a date object is one way (see mplungjan's answer) or you can convert them to a common unit (say seconds) and subtract:

function toSeconds(t) {
    var bits = t.split(':');
    return bits[0]*3600 + bits[1]*60 + bits[2]*1;
}

var secs1 = toSeconds(time1);
var secs2 = toSeconds(time2);

// do stuff  - compare, subtract, less than, greater than, whatever