form.st_dob = '04052016';

  writedump(isValid('date', form.st_dob));
  writedump(isDate(form.st_dob));
  writedump(dateDiff('d', now(), form.st_dob));
  writedump(now().diff('d', form.st_dob));

make this make sense - these kind of inconsistencies are nuts

works on Lucee, interesting

form.st_dob is a string, and it should be incumbent on you to validate that the string representation is valid before doing any date stuff with it, imo. i'd treat it like a string and validate against regexes before testing with the bif for the reasons you're seeing

Practically speaking I agree, but that said, wth with the bif? A validation function that requires you to validate the data before using it has missed the point IMO.

i don't disagree, date validation has been sketchy with cf for a long time, not sure what to say

I think there's a point being missed here

guess i missed that, yeah. that's a very good point, i like the way you comb your hair around it.

It's not to do with string/date ambiguity. It's to do with CF being shite

i withdraw everything i said up to the combing part

@John Varady your example could have been clearer, that said. And your question.

also the point about

isDate()

and

isValid( 'date' )

having different definitions of a valid date, no?

i seem to recall isValid being the preferred replacement for isDate because of 'better' date validation?

I didn't even notice that. f***in hell.

sorry for not being clearer - my issue came down to this if/else falling through and throwing a hard error when I expected the date to be valid. Also I like to use the member functions whenever possible but they should have the same results as the function equivalent

if (!isValid('date', form.st_dob)) {
      flash.error('Date of birth is required.');
    } else if (now().diff('d', form.st_dob) < 0) {
      flash.error('Date of birth is in the future.');
    } else if (now().diff('yyyy', form.st_dob) > 20) {
      flash.error('Date of birth is past deadline. Student is over 20 years old.');
    }

@Mark Takata (Adobe) this is where you come in  :wink:

Not at 6am I don't LOL

HAHAHA

s'ok. I'm in training so I had to get up anyway lmao