call method

@override String? call(T? value)

Implementation

@override
String? call(T? value) {
  var min = this.min;
  var max = this.max;
  if (value == null) return null;
  if (min != null && max != null) {
    if (value.toString().length < min || value.toString().length > max) {
      return 'Requires a value between $min and $max characters long';
    }
  } else if (min != null) {
    if (value.toString().length < min) {
      return 'Requires a value at least $min character(s) long';
    }
  } else if (max != null) {
    if (value.toString().length > max) {
      return 'Requires a value less than or equal to $max character(s) long';
    }
  }
  return null;
}