For running J!5.1 you must https://fabrikar.com/forums/index.php?wiki/update-from-github/ or include the new file manually https://fabrikar.com/forums/index.php?threads/joomla-5-1-and-fabrik-cannot-find-files-error.54473/post-285151 See also Announcements
Please see our announcement here.
requirejs(['fab/fabrik'], function () {
Fabrik.addEvent('fabrik.element.date.calendar.created', function (el) {
// check to see if this is one of the dates we need to set
if (el.strElement == 'yourtable___date1' || el.strElement == 'yourtable___date2') {
// cal the date picker widget's setDate function
el.cal.setDate(new Date('2016-10-01'));
}
}