Question

I have two values that are used for the amount of time it will take to complete a task. How can I add these values together to come up with a total number of hours and minutes, but still have the value account for 60 minutes equalling one hour?

The two values I’d like to get the sum of and the total value are in HH:MM (00:00) format.

Thanks!

Answer 1

Here’s something I had laying around. It allows for an infinite number of arguments, so you could have addTime('01:00') or addTime('01:00', '02:00', '03:00', '04:00'), etc. It’s three functions long because it also verifies if the times entered are properly formatted, and if not, then it formats them. (E.g. Ensures that minutes is 2 digits long, and if hours is 1 digit long, then pad it with one zero, etc.)

You can play with it here: http://jsfiddle.net/WyxwU/

It’s also here:

var totalTime = addTime('12:34', '56:12', '78:45');
document.write(totalTime);

function addTime()
{
    if (arguments.length < 2)
    {
        if (arguments.length == 1 && isFormattedDate(arguments[0])) return arguments[0];
        else return false;
    }

    var time1Split, time2Split, totalHours, totalMinutes;
    if (isFormattedDate(arguments[0])) var totalTime = arguments[0];
    else return false;

    for (var i = 1; i < arguments.length; i++)
    {
        // Add them up
        time1Split = totalTime.split(':');
        time2Split = arguments[i].split(':');

        totalHours = parseInt(time1Split[0]) + parseInt(time2Split[0]);
        totalMinutes = parseInt(time1Split[1]) + parseInt(time2Split[1]);

        // If total minutes is more than 59, then convert to hours and minutes
        if (totalMinutes > 59)
        {
            totalHours += Math.floor(totalMinutes / 60);
            totalMinutes = totalMinutes % 60;
        }

        totalTime = totalHours + ':' + padWithZeros(totalMinutes);
    }

    return totalTime;
}

function isFormattedDate(date)
{
    var splitDate = date.split(':');
    if (splitDate.length == 2 && (parseInt(splitDate[0]) + '').length <= 2 && (parseInt(splitDate[1]) + '').length <= 2) return true;
    else return false;
}

function padWithZeros(number)
{
    var lengthOfNumber = (parseInt(number) + '').length;
    if (lengthOfNumber == 2) return number;
    else if (lengthOfNumber == 1) return '0' + number;
    else if (lengthOfNumber == 0) return '00';
    else return false;
}