Dart - Bỏ dấu tiếng Việt - diacritic

 //https://github.com/agilord/diacritic

// Bỏ dấu tiếng Việt
String removeDiacritics(String text) =>
    new String.fromCharCodes(replaceCodeUnits(text.codeUnits));

bool _initialized = false;
Map<int, int> _singleUnit = {};
Map<int, List<int>> _multiUnit = {};

void _register(String base, String accents) {
  if (base.codeUnits.length == 1) {
    final int baseUnit = base.codeUnits.first;
    for (int unit in accents.codeUnits) {
      _singleUnit[unit] = baseUnit;
    }
  } else {
    for (int unit in accents.codeUnits) {
      _multiUnit[unit] = base.codeUnits;
    }
  }
}

/// Replaces list of code units to a simplified list.
/// The length of the result list may differ from the source.
List<int> replaceCodeUnits(List<int> codeUnits) {
  _initIfRequired();
  final List<int> result = [];
  for (int original in codeUnits) {
    // Combining Diacritical Marks in Unicode
    if (original >= 0x0300 && original <= 0x036F) {
      continue;
    }

    // single-unit replacements
    final int single = _singleUnit[original];
    if (single != null) {
      result.add(single);
      continue;
    }

    // multi-unit replacements
    final List<int> multiple = _multiUnit[original];
    if (multiple != null) {
      result.addAll(multiple);
      continue;
    }

    // no replacement
    result.add(original);
  }
  return result;
}

void _initIfRequired() {
  if (_initialized) return;
  _register(' ', '\u00A0');
  _register('A',
      '\u0041\u24B6\uFF21\u00C0\u00C1\u00C2\u1EA6\u1EA4\u1EAA\u1EA8\u00C3\u0100\u0102\u1EB0\u1EAE\u1EB4\u1EB2\u0226\u01E0\u00C4\u01DE\u1EA2\u00C5\u01FA\u01CD\u0200\u0202\u1EA0\u1EAC\u1EB6\u1E00\u0104\u023A\u2C6F');
  _register('AA', '\uA732');
  _register('AE', '\u00C6\u01FC\u01E2');
  _register('AO', '\uA734');
  _register('AU', '\uA736');
  _register('AV', '\uA738\uA73A');
  _register('AY', '\uA73C');
  _register('B', '\u0042\u24B7\uFF22\u1E02\u1E04\u1E06\u0243\u0182\u0181');
  _register('C',
      '\u0043\u24B8\uFF23\u0106\u0108\u010A\u010C\u00C7\u1E08\u0187\u023B\uA73E');
  _register('D',
      '\u0044\u24B9\uFF24\u1E0A\u010E\u1E0C\u1E10\u1E12\u1E0E\u0110\u018B\u018A\u0189\uA779');
  _register('DZ', '\u01F1\u01C4');
  _register('Dz', '\u01F2\u01C5');
  _register('E',
      '\u0045\u24BA\uFF25\u00C8\u00C9\u00CA\u1EC0\u1EBE\u1EC4\u1EC2\u1EBC\u0112\u1E14\u1E16\u0114\u0116\u00CB\u1EBA\u011A\u0204\u0206\u1EB8\u1EC6\u0228\u1E1C\u0118\u1E18\u1E1A\u0190\u018E');
  _register('F', '\u0046\u24BB\uFF26\u1E1E\u0191\uA77B');
  _register('G',
      '\u0047\u24BC\uFF27\u01F4\u011C\u1E20\u011E\u0120\u01E6\u0122\u01E4\u0193\uA7A0\uA77D\uA77E');
  _register('H',
      '\u0048\u24BD\uFF28\u0124\u1E22\u1E26\u021E\u1E24\u1E28\u1E2A\u0126\u2C67\u2C75\uA78D');
  _register('I',
      '\u0049\u24BE\uFF29\u00CC\u00CD\u00CE\u0128\u012A\u012C\u0130\u00CF\u1E2E\u1EC8\u01CF\u0208\u020A\u1ECA\u012E\u1E2C\u0197');
  _register('J', '\u004A\u24BF\uFF2A\u0134\u0248');
  _register('K',
      '\u004B\u24C0\uFF2B\u1E30\u01E8\u1E32\u0136\u1E34\u0198\u2C69\uA740\uA742\uA744\uA7A2');
  _register('L',
      '\u004C\u24C1\uFF2C\u013F\u0139\u013D\u1E36\u1E38\u013B\u1E3C\u1E3A\u0141\u023D\u2C62\u2C60\uA748\uA746\uA780');
  _register('LJ', '\u01C7');
  _register('Lj', '\u01C8');
  _register('M', '\u004D\u24C2\uFF2D\u1E3E\u1E40\u1E42\u2C6E\u019C');
  _register('N',
      '\u004E\u24C3\uFF2E\u01F8\u0143\u00D1\u1E44\u0147\u1E46\u0145\u1E4A\u1E48\u0220\u019D\uA790\uA7A4');
  _register('NJ', '\u01CA');
  _register('Nj', '\u01CB');
  _register('O',
      '\u004F\u24C4\uFF2F\u00D2\u00D3\u00D4\u1ED2\u1ED0\u1ED6\u1ED4\u00D5\u1E4C\u022C\u1E4E\u014C\u1E50\u1E52\u014E\u022E\u0230\u00D6\u022A\u1ECE\u0150\u01D1\u020C\u020E\u01A0\u1EDC\u1EDA\u1EE0\u1EDE\u1EE2\u1ECC\u1ED8\u01EA\u01EC\u00D8\u01FE\u0186\u019F\uA74A\uA74C');
  _register('OI', '\u01A2');
  _register('OO', '\uA74E');
  _register('OU', '\u0222');
  _register(
      'P', '\u0050\u24C5\uFF30\u1E54\u1E56\u01A4\u2C63\uA750\uA752\uA754');
  _register('Q', '\u0051\u24C6\uFF31\uA756\uA758\u024A');
  _register('R',
      '\u0052\u24C7\uFF32\u0154\u1E58\u0158\u0210\u0212\u1E5A\u1E5C\u0156\u1E5E\u024C\u2C64\uA75A\uA7A6\uA782');
  _register('S',
      '\u0053\u24C8\uFF33\u1E9E\u015A\u1E64\u015C\u1E60\u0160\u1E66\u1E62\u1E68\u0218\u015E\u2C7E\uA7A8\uA784');
  _register('T',
      '\u0054\u24C9\uFF34\u1E6A\u0164\u1E6C\u021A\u0162\u1E70\u1E6E\u0166\u01AC\u01AE\u023E\uA786');
  _register('Th', '\u00DE');
  _register('TZ', '\uA728');
  _register('U',
      '\u0055\u24CA\uFF35\u00D9\u00DA\u00DB\u0168\u1E78\u016A\u1E7A\u016C\u00DC\u01DB\u01D7\u01D5\u01D9\u1EE6\u016E\u0170\u01D3\u0214\u0216\u01AF\u1EEA\u1EE8\u1EEE\u1EEC\u1EF0\u1EE4\u1E72\u0172\u1E76\u1E74\u0244');
  _register('V', '\u0056\u24CB\uFF36\u1E7C\u1E7E\u01B2\uA75E\u0245');
  _register('VY', '\uA760');
  _register(
      'W', '\u0057\u24CC\uFF37\u1E80\u1E82\u0174\u1E86\u1E84\u1E88\u2C72');
  _register('X', '\u0058\u24CD\uFF38\u1E8A\u1E8C');
  _register('Y',
      '\u0059\u24CE\uFF39\u1EF2\u00DD\u0176\u1EF8\u0232\u1E8E\u0178\u1EF6\u1EF4\u01B3\u024E\u1EFE');
  _register('Z',
      '\u005A\u24CF\uFF3A\u0179\u1E90\u017B\u017D\u1E92\u1E94\u01B5\u0224\u2C7F\u2C6B\uA762');
  _register('a',
      '\u0061\u24D0\uFF41\u1E9A\u00E0\u00E1\u00E2\u1EA7\u1EA5\u1EAB\u1EA9\u00E3\u0101\u0103\u1EB1\u1EAF\u1EB5\u1EB3\u0227\u01E1\u00E4\u01DF\u1EA3\u00E5\u01FB\u01CE\u0201\u0203\u1EA1\u1EAD\u1EB7\u1E01\u0105\u2C65\u0250\u0251');
  _register('aa', '\uA733');
  _register('ae', '\u00E6\u01FD\u01E3');
  _register('ao', '\uA735');
  _register('au', '\uA737');
  _register('av', '\uA739\uA73B');
  _register('ay', '\uA73D');
  _register('b', '\u0062\u24D1\uFF42\u1E03\u1E05\u1E07\u0180\u0183\u0253');
  _register('c',
      '\u0063\u24D2\uFF43\u0107\u0109\u010B\u010D\u00E7\u1E09\u0188\u023C\uA73F\u2184');
  _register('d',
      '\u0064\u24D3\uFF44\u1E0B\u010F\u1E0D\u1E11\u1E13\u1E0F\u0111\u018C\u0256\u0257\uA77A');
  _register('dz', '\u01F3\u01C6');
  _register('e',
      '\u0065\u24D4\uFF45\u00E8\u00E9\u00EA\u1EC1\u1EBF\u1EC5\u1EC3\u1EBD\u0113\u1E15\u1E17\u0115\u0117\u00EB\u1EBB\u011B\u0205\u0207\u1EB9\u1EC7\u0229\u1E1D\u0119\u1E19\u1E1B\u0247\u025B\u01DD');
  _register('f', '\u0066\u24D5\uFF46\u1E1F\u0192\uA77C');
  _register('ff', '\uFB00');
  _register('fi', '\uFB01');
  _register('fl', '\uFB02');
  _register('ffi', '\uFB03');
  _register('ffl', '\uFB04');
  _register('g',
      '\u0067\u24D6\uFF47\u01F5\u011D\u1E21\u011F\u0121\u01E7\u0123\u01E5\u0260\uA7A1\u1D79\uA77F');
  _register('h',
      '\u0068\u24D7\uFF48\u0125\u1E23\u1E27\u021F\u1E25\u1E29\u1E2B\u1E96\u0127\u2C68\u2C76\u0265');
  _register('hv', '\u0195');
  _register('i',
      '\u0069\u24D8\uFF49\u00EC\u00ED\u00EE\u0129\u012B\u012D\u00EF\u1E2F\u1EC9\u01D0\u0209\u020B\u1ECB\u012F\u1E2D\u0268\u0131');
  _register('j', '\u006A\u24D9\uFF4A\u0135\u01F0\u0249');
  _register('k',
      '\u006B\u24DA\uFF4B\u1E31\u01E9\u1E33\u0137\u1E35\u0199\u2C6A\uA741\uA743\uA745\uA7A3');
  _register('l',
      '\u006C\u24DB\uFF4C\u0140\u013A\u013E\u1E37\u1E39\u013C\u1E3D\u1E3B\u017F\u0142\u019A\u026B\u2C61\uA749\uA781\uA747');
  _register('lj', '\u01C9');
  _register('m', '\u006D\u24DC\uFF4D\u1E3F\u1E41\u1E43\u0271\u026F');
  _register('n',
      '\x6E\xF1\u006E\u24DD\uFF4E\u01F9\u0144\u00F1\u1E45\u0148\u1E47\u0146\u1E4B\u1E49\u019E\u0272\u0149\uA791\uA7A5\u043B\u0509');
  _register('nj', '\u01CC');
  _register('o',
      '\u07C0\u006F\u24DE\uFF4F\u00F2\u00F3\u00F4\u1ED3\u1ED1\u1ED7\u1ED5\u00F5\u1E4D\u022D\u1E4F\u014D\u1E51\u1E53\u014F\u022F\u0231\u00F6\u022B\u1ECF\u0151\u01D2\u020D\u020F\u01A1\u1EDD\u1EDB\u1EE1\u1EDF\u1EE3\u1ECD\u1ED9\u01EB\u01ED\u00F8\u01FF\u0254\uA74B\uA74D\u0275');
  _register('oe', '\u0152\u0153');
  _register('oi', '\u01A3');
  _register('ou', '\u0223');
  _register('oo', '\uA74F');
  _register(
      'p', '\u0070\u24DF\uFF50\u1E55\u1E57\u01A5\u1D7D\uA751\uA753\uA755');
  _register('q', '\u0071\u24E0\uFF51\u024B\uA757\uA759');
  _register('r',
      '\u0072\u24E1\uFF52\u0155\u1E59\u0159\u0211\u0213\u1E5B\u1E5D\u0157\u1E5F\u024D\u027D\uA75B\uA7A7\uA783');
  _register('s',
      '\u0073\u24E2\uFF53\u00DF\u015B\u1E65\u015D\u1E61\u0161\u1E67\u1E63\u1E69\u0219\u015F\u023F\uA7A9\uA785\u1E9B');
  _register('ss', '\xDF');
  _register('t',
      '\u0074\u24E3\uFF54\u1E6B\u1E97\u0165\u1E6D\u021B\u0163\u1E71\u1E6F\u0167\u01AD\u0288\u2C66\uA787');
  _register('th', '\u00FE');
  _register('tz', '\uA729');
  _register('u',
      '\u0075\u24E4\uFF55\u00F9\u00FA\u00FB\u0169\u1E79\u016B\u1E7B\u016D\u00FC\u01DC\u01D8\u01D6\u01DA\u1EE7\u016F\u0171\u01D4\u0215\u0217\u01B0\u1EEB\u1EE9\u1EEF\u1EED\u1EF1\u1EE5\u1E73\u0173\u1E77\u1E75\u0289');
  _register('v', '\u0076\u24E5\uFF56\u1E7D\u1E7F\u028B\uA75F\u028C');
  _register('vy', '\uA761');
  _register('w',
      '\u0077\u24E6\uFF57\u1E81\u1E83\u0175\u1E87\u1E85\u1E98\u1E89\u2C73');
  _register('x', '\u0078\u24E7\uFF58\u1E8B\u1E8D');
  _register('y',
      '\u0079\u24E8\uFF59\u1EF3\u00FD\u0177\u1EF9\u0233\u1E8F\u00FF\u1EF7\u1E99\u1EF5\u01B4\u024F\u1EFF');
  _register('z',
      '\u007A\u24E9\uFF5A\u017A\u1E91\u017C\u017E\u1E93\u1E95\u01B6\u0225\u0240\u2C6C\uA763');
  _initialized = true;
}