How to add unique mobile number function in Magento 2 registration form?

Question

I used this link How can i add a field mobile number at the time of customer registration form in magento 2? to add mobile number field in the registration form which works fine. But I need to validate mobile number to be unique, min and max of 10 digits.

Answer 1

data-validate="{maxlength:10, minlength:0}" 

OR

data-validate="{rangelength:[0, 10]}" 

And for unique you must do it in your controller