Can you use the existence of a hidden field as a logic condition?

We’re using Typeform to supplement a leads flow where a user will potentially fill out optional data before reaching the form. In this case, there’s an optional phone number field in the application that we’re passing to the Typeform. I’d like to change the logic flow if that phone number is passed using a hidden field, but I don’t have any other criteria besides its existence.

When I use the logic feature, it requires me to check the hidden field against a condition (is exactly, contains etc). Is there a way to just check that it exists or not, rather than what the data actually contains?