lengthIsInRange method

String? lengthIsInRange({
  1. int? minLength = 0,
  2. int? maxLength = 25,
  3. String? valueName,
})

lengthIsInRange compares the length of a string to the minLength and maxLength to ensure it is between the given values. Provides a basic error message that can be used. 'valueName must be between minLength and maxLength characters long.' A return value of null indicates a valid length.

thows an ArgumentError if valueName is null or the String value is null.

Implementation

String? lengthIsInRange({
  int? minLength = 0,
  int? maxLength = 25,
  String? valueName,
}) {
  if (this == null) {
    throw ArgumentError('value is required', this);
  }
  return this!.length < minLength! || this!.length > maxLength!
      ? '$valueName must be between $minLength and $maxLength characters long'
      : null;
}