Filter unicode symbols by code

main.dart

/*
 * Filter unicode symbols by code
 * https://gist.github.com/PlugFox/9c7bbfabcea80d41d380b4ee8ae4c75d
 * https://dartpad.dev/9c7bbfabcea80d41d380b4ee8ae4c75d?id=&null_safety=true
 */

import 'dart:math' as math;

const String source = r'#51\J-!dv@dT_o6w^iж,7nдomzGpаWq0ЁKlGsH"~!UZHdпф5i3`N(';

void main() => print(
      String.fromCharCodes(
        source.codeUnits.where((i) =>
            UTF8CodeUnitsX.isDigit(i) ||
            UTF8CodeUnitsX.isLatin(i) ||
            UTF8CodeUnitsX.isCyrillic(i)),
      ),
    );

extension UTF8CodeUnitsX on List<int> {
  /// 0..9: 48..57
  static bool isDigit(i) => i > 47 && i < 58;

  /// A..Z: 65..90
  /// a..z: 97..122
  static bool isLatin(i) => (i > 64 && i < 91) || (i > 96 && i < 123);

  /// Ё:    1025
  /// А..Я: 1040..1071
  /// а..я: 1072..1103
  /// ё:    1105
  static bool isCyrillic(i) => (i > 1039 && i < 1104) || i == 1025 || i == 1105;

  Iterable<int> get onlyDigits => where(isDigit);

  Iterable<int> get onlyLatin => where(isLatin);

  Iterable<int> get onlyCyrillic => where(isCyrillic);

  /// Maximum code
  int get max => reduce(math.max);

  /// Minimum code
  int get min => reduce(math.min);
}