isAlphabetical method

Validator isAlphabetical({
  1. String message = "Validator.isAlphabetical",
})

Returns a Validator that accepts a value that is comprised of only letters, or empty.

https://stackoverflow.com/questions/20690499/concrete-javascript-regular-expression-for-accented-characters-diacritics https://unicode-table.com/en/ accepts

null, "", " ", "foo", " foo", "foo ", "foo bar", " foo bar "

rejects

"0", "X Æ A-12",

Implementation

Validator isAlphabetical({
  String message = "Validator.isAlphabetical",
}) {
  var source = r"^([A-Za-zÀ-ÖØ-öø-ÿ]* *)*$";
  return copy().matches(RegExp(source, unicode: true), message: message);
}