ReqDigit.len constructor
Constrains the input data to the digits 0-9
and its length (number of
digits) to len
digits.
len
the number of digits; it must be > 0.
blank
the error message in case of a null or empty input value.
mal
the error message if a non-digit character is found.
diff
the error message if the number of digits is different from len
.
Implementation
ReqDigit.len(int len, {String? blank, String? mal, String? diff})
: this._dig(Digit.len(len, mal: mal, diff: diff), blank);