validate method
Implementation
@override
String? validate(String? value, bool required, Map<String, dynamic> data) {
if (value != null) {
if (!required && value.isEmpty) {
return null;
}
if (exact != null && value.length != exact!) {
return short
? 'Need $exact characters'
: 'Need exact $exact characters';
}
if (min != null && value.length < min!) {
return short ? 'Need $min characters' : 'Longer than $min characters';
}
if (max != null && value.length > max!) {
return short ? 'Only $max characters' : 'Lesser than $max characters';
}
}
return null;
}