JavaScript seconds to time string with format hh:mm:ss

Question

I want to convert a duration of time, i.e., number of seconds to colon-separated time string (hh:mm:ss)

I found some useful answers here but they all talk about conv

Answer 1

I'm personally prefer the leading unit (days, hours, minutes) without leading zeros. But seconds should always be leaded by minutes (0:13), this presentation is easily considered as 'duration', without further explanation (marking as min, sec(s), etc.), usable in various languages (internationalization).

    // returns  (-)d.h:mm:ss(.f)
    //          (-)h:mm:ss(.f)
    //          (-)m:ss(.f)
    function formatSeconds (value, fracDigits) {
        var isNegative = false;
        if (isNaN(value)) {
            return value;
        } else if (value < 0) {
            isNegative = true;
            value = Math.abs(value);
        }
        var days = Math.floor(value / 86400);
        value %= 86400;
        var hours = Math.floor(value / 3600);
        value %= 3600;
        var minutes = Math.floor(value / 60);
        var seconds = (value % 60).toFixed(fracDigits || 0);
        if (seconds < 10) {
            seconds = '0' + seconds;
        }

        var res = hours ? (hours + ':' + ('0' + minutes).slice(-2) + ':' + seconds) : (minutes + ':' + seconds);
        if (days) {
            res = days + '.' + res;
        }
        return (isNegative ? ('-' + res) : res);
    }

//imitating the server side (.net, C#) duration formatting like:

    public static string Format(this TimeSpan interval)
    {
        string pattern;
        if (interval.Days > 0)          pattern = @"d\.h\:mm\:ss";
        else if (interval.Hours > 0)    pattern = @"h\:mm\:ss";
        else                            pattern = @"m\:ss";
        return string.Format("{0}", interval.ToString(pattern));
    }