unicode fun in dart

console

===[🌈]===
  length:    2
  codeunits: 2
  runes:     1
  utf16:     0xd83c 0xdf08
  utf8len:    4
  utf8 bytes: 0xf0 0x9f 0x8c 0x88
===[Hello🌎]===
  length:    7
  codeunits: 7
  runes:     6
  utf16:     0x0048 0x0065 0x006c 0x006c 0x006f 0xd83c 0xdf0e
  utf8len:    9
  utf8 bytes: 0x48 0x65 0x6c 0x6c 0x6f 0xf0 0x9f 0x8c 0x8e
===[🏳️‍🌈]===
  length:    6
  codeunits: 6
  runes:     4
  utf16:     0xd83c 0xdff3 0xfe0f 0x200d 0xd83c 0xdf08
  utf8len:    14
  utf8 bytes: 0xf0 0x9f 0x8f 0xb3 0xef 0xb8 0x8f 0xe2 0x80 0x8d 0xf0 0x9f 0x8c 0x88
===[🏳️‍]===
  length:    4
  codeunits: 4
  runes:     3
  utf16:     0xd83c 0xdff3 0xfe0f 0x200d
  utf8len:    10
  utf8 bytes: 0xf0 0x9f 0x8f 0xb3 0xef 0xb8 0x8f 0xe2 0x80 0x8d

unicode.dart

import 'dart:convert';

main() {
  printIt(String sup) {
    print('===[$sup]===');
    print('  length:    ${sup.length}');
    print('  codeunits: ${sup.codeUnits.length}');
    print('  runes:     ${sup.runes.length}');

    var hex =
        sup.codeUnits.map((d) => '0x${d.toRadixString(16).padLeft(4, '0')}');
    print('  utf16:     ${hex.join(' ')}');

    var utf8bytes = utf8.encode(sup);
    hex =
        utf8bytes.map((d) => '0x${d.toRadixString(16).padLeft(2, '0')}');
    print('  utf8len:    ${utf8bytes.length}');
    print('  utf8 bytes: ${hex.join(' ')}');
  }
  printIt('🌈');
  printIt('Hello🌎');
  printIt('🏳️‍🌈');
  printIt('🏳️‍');
}