Bug in TimeStep.prototype.getClassName

I dont find it in forum, and it look like a bug :

TimeStep.prototype.getClassName : case 'day': (and maybe some other)

return 'vis-day' + current.date() + ' vis-' + current.format('MMMM').toLowerCase() + today(current) + currentMonth(current) + this.step <= 2 ? today(current) : '' + this.step <= 2 ? ' vis-' + current.format('dddd').toLowerCase() : '' + even(current.date() - 1);

the first part : 'vis-day' + current.date() + ' vis-' + current.format('MMMM').toLowerCase() + today(current) + currentMonth(current) is used in condition calculation, and therefore, never added in html Some bracket may be needed