Workaround: evaluate regex constraint before submission of form

Matt-Goodman

A known deficiency with the current version of Survey123 Connect is that it does not evaluate constraints until form submission. Many users have the need or desire to have their surveys evaluate a regular expression constraint before proceeding to the next question or next page in their form (more on the problem here).

Below is a possible (although somewhat clunky) work-around. It uses 'note' type rows so that no new fields are required in the data schema. 

1. Identify the data field row that you want to validate with regex and insert two new rows below it.
2. Set both new row types to 'note'.
3. For the first note, make its 'appearance' hidden and write an 'if' expression in the 'calculation' column that evaluates your regex expression, returning some simple Boolean-like values like OK/bad, True/False, Yes/No, etc. Example:  if(regex(${field2check}, '^[a-zA-Z]'), "OK", "bad")
4. For the second note row, leave its 'appearance' visible, but set its 'relevant' column to ${field2check}!="" and ${calc_row}!="OK" (this means that this note will not be visible unless the field that you're trying to validate is not blank and it has been evaluated as not "OK" by the calculation done in the row above. Set the text ('label') for this row to whatever you want your error message to be. 
   
   Here is a simplified example:
   

   type	name	label	appearance	required	required_message	calculation	constraint	constraint_message::default	constraint_message	relevant
   begin group	user_info	User Info	field-list
   text	name	Name		yes	Enter a valid name to proceed
   note	namecheck	namecheck	hidden			if(regex(${name}, '^[a-zA-Z]'), "OK", "")
   note	nameerrornote	Enter a valid name to proceed								${name}!="" and ${namecheck}!="OK"
   range	age	Age		yes						${namecheck}="OK"
   text	additionalnotes	Additional Notes								${age}!=""
   end group

There may be more elegant workarounds, so if you're aware of ways to make this more slick, please comment. 

jcarlson

I think it's a solid workaround, similar to what we do for immediate feedback on some of our forms.

Edit to add: if there's a better way to accomplish this, I'd love to know, too!