Return the Repeatable Latest Date

This will return the latest date captured in a date field that is in a repeatable section.

var dates = REPEATABLEVALUES($inspections, 'rep_date') || [];

SETRESULT(LAST(dates.sort()));

Or if you need to customize the logic for how it gets calculated, you can use this equivalent example:

var dates = REPEATABLEVALUES($repeatable_section, 'date_field');
var maxDate;

if (dates && dates.length > 0) {
  maxDate = dates[0];

  dates.forEach(function(currentDate) {
    if (currentDate > maxDate) {
      maxDate = currentDate;
    }
  });

  SETRESULT(maxDate);
}