Partial Date Entry Validation

[JonathanDsouza6]

Description
I have a form with an optional date picker field, but I want to display an error message when the user enters only part of the date.

Expected Behavior
If the user fills in only the day and month but leaves the year blank, an error message should be shown to indicate that the date is incomplete.

Question
What would be the best way to handle this validation? Are there any recommended approaches or best practices for detecting and handling partial date inputs?

Thanks in advance for your help!