Way to validate if value equals to defaultValue

[kwiat1990]

Hey, is there any way to run validation in a case where form gets populated with default values and can be only valid if its values while submitting are different from those default ones? One use case is if the user edit his comment and I don't want to trigger a request if he doesn't change the value. I'm interested in showing a validation error. Otherwise, it's not a problem to disable submit button or call event.preventDefault() but it's not what I want.