add: if (!aDate) { return null; } 
context: function ensureDateTime(aDate) {    if (!aDate.isDate) {        return aDate;    }    var newDate = aDate.clone();    newDate.hour = 0;    newDate.minute = 0;    newDate.second = 0;    newDate.isDate = false;    return newDate;}
meta: 10234	/local1/tlutelli/issta_data/temp/all_js/javascript/2007_temp/2007/10234/494dee1ea04969308490b6929bf872e75b90f366/calUtils.js/buggy/calendar/base/src/calUtils.js