Function formatTime

src/lib/dates.js:418–452

(x, tr)

 */
var MAXSECONDS = [59, 59.9, 59.99, 59.999, 59.9999];
function formatTime(x, tr) {
    var timePart = mod(x + 0.05, ONEDAY);

    var timeStr = lpad(Math.floor(timePart / ONEHOUR), 2) + ':' +
        lpad(mod(Math.floor(timePart / ONEMIN), 60), 2);

    if(tr !== 'M') {
        if(!isNumeric(tr)) tr = 0; // should only be 'S'

        /*
         * this is a weird one - and shouldn't come up unless people
         * monkey with tick0 in weird ways, but we need to do something!
         * IN PARTICULAR we had better not display garbage (see below)
         * for numbers we always round to the nearest increment of the
         * precision we're showing, and this seems like the right way to
         * handle seconds and milliseconds, as they have a decimal point
         * and people will interpret that to mean rounding like numbers.
         * but for larger increments we floor the value: it's always
         * 2013 until the ball drops on the new year. We could argue about
         * which field it is where we start rounding (should 12:08:59
         * round to 12:09 if we're stopping at minutes?) but for now I'll
         * say we round seconds but floor everything else. BUT that means
         * we need to never round up to 60 seconds, ie 23:59:60
         */
        var sec = Math.min(mod(x / ONESEC, 60), MAXSECONDS[tr]);

        var secStr = (100 + sec).toFixed(tr).slice(1);
        if(tr > 0) {
            secStr = secStr.replace(/0+$/, '').replace(/[\.]$/, '');
        }

        timeStr += ':' + secStr;
    }
    return timeStr;
}

/*
 * formatDate: turn a date into tick or hover label text.