positive method
Ensures that the numeric value is positive (greater than 0).
This method adds a PositiveValidator to check whether the value is strictly greater than zero.
Example
final validator = v.num().positive();
print(validator.validate(5)); // true (valid)
print(validator.validate(0)); // false (invalid)
print(validator.validate(-3)); // false (invalid)
Parameters
message(optional): A custom validation message.
Returns
The current VNumber<T> instance with the positive validation applied.
Implementation
VNumber<T> positive({String? message}) {
add(PositiveValidator(message: message!));
return this;
}