JAVASCRIPT: subtracting Time and getting its number of minutes

Question

For Example:

StartTime = 00:10;
EndTIme = 01:20;

These variables are string

Question: How can i Subtract them and returning the span time in minutes?

Hope you can help

Answer 1

var startTime = "0:10";
var endTime = "1:20";

var s = startTime.split(':');
var e = endTime.split(':');

var end = new Date(0, 0, 0, parseInt(e[1], 10), parseInt(e[0], 10), 0);
var start = new Date(0, 0, 0, parseInt(s[1], 10), parseInt(s[0], 10), 0);

var elapsedMs = end-start;
var elapsedMinutes = elapsedMs / 1000 / 60;

Answer 2

If you're going to be doing a lot of date/time manipulation, it's worth checking out date.js.

However, if you're just trying to solve this one problem, here's an algorithm off the top of my head.

(1)Parse start/end values to get hours and minutes, (2)Convert hours to minutes, (3)Subtract

function DifferenceInMinutes(start, end) {
    var totalMinutes = function(value) {
        var match = (/(\d{1,2}):(\d{1,2})/g).exec(value);
        return (Number(match[1]) * 60) + Number(match[2]);
    }    
    return totalMinutes(end) - totalMinutes(start);
}

Answer 3

dojo.date.difference is built for the task - just ask for a "minute" interval.

Get the difference in a specific unit of time (e.g., number of months, weeks, days, etc.) between two dates, rounded to the nearest integer.

Usage:

var foo: Number (integer)=dojo.date.difference(date1: Date, date2: Date?, interval: String?);

Answer 4

Make a function to parse a string like that into minutes:

function parseTime(s) {
   var c = s.split(':');
   return parseInt(c[0]) * 60 + parseInt(c[1]);
}

Now you can parse the strings and just subtract:

var minutes = parseTime(EndTIme) - parseTime(StartTime);