Replacing diacritics in Javascript

Question

How can I replace diacritics (ă,ş,ţ etc) with their "normal" form (a,s,t) in javascript?

Answer 1

In modern browsers and node.js you can use unicode normalization to decompose those characters followed by a filtering regex.

str.normalize('NFKD').replace(/[^\w]/g, '')

If you wanted to allow characters such as whitespaces, dashes, etc. you should extend the regex to allow them.

str.normalize('NFKD').replace(/[^\w\s.-_\/]/g, '')

var str = 'áàâäãéèëêíìïîóòöôõúùüûñçăşţ';
var asciiStr = str.normalize('NFKD').replace(/[^\w]/g, '');
console.info(str, asciiStr);

NOTES: This method does not work with characters that do not have unicode composed varian. i.e. ø and ł

Answer 2

A more complete version with case sensitive support, ligatures and whatnot. Original source at: http://lehelk.com/2011/05/06/script-to-remove-diacritics/

var defaultDiacriticsRemovalMap = [
    {'base':'A', 'letters':/[\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]/g},
    {'base':'AA','letters':/[\uA732]/g},
    {'base':'AE','letters':/[\u00C6\u01FC\u01E2]/g},
    {'base':'AO','letters':/[\uA734]/g},
    {'base':'AU','letters':/[\uA736]/g},
    {'base':'AV','letters':/[\uA738\uA73A]/g},
    {'base':'AY','letters':/[\uA73C]/g},
    {'base':'B', 'letters':/[\u0042\u24B7\uFF22\u1E02\u1E04\u1E06\u0243\u0182\u0181]/g},
    {'base':'C', 'letters':/[\u0043\u24B8\uFF23\u0106\u0108\u010A\u010C\u00C7\u1E08\u0187\u023B\uA73E]/g},
    {'base':'D', 'letters':/[\u0044\u24B9\uFF24\u1E0A\u010E\u1E0C\u1E10\u1E12\u1E0E\u0110\u018B\u018A\u0189\uA779]/g},
    {'base':'DZ','letters':/[\u01F1\u01C4]/g},
    {'base':'Dz','letters':/[\u01F2\u01C5]/g},
    {'base':'E', 'letters':/[\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]/g},
    {'base':'F', 'letters':/[\u0046\u24BB\uFF26\u1E1E\u0191\uA77B]/g},
    {'base':'G', 'letters':/[\u0047\u24BC\uFF27\u01F4\u011C\u1E20\u011E\u0120\u01E6\u0122\u01E4\u0193\uA7A0\uA77D\uA77E]/g},
    {'base':'H', 'letters':/[\u0048\u24BD\uFF28\u0124\u1E22\u1E26\u021E\u1E24\u1E28\u1E2A\u0126\u2C67\u2C75\uA78D]/g},
    {'base':'I', 'letters':/[\u0049\u24BE\uFF29\u00CC\u00CD\u00CE\u0128\u012A\u012C\u0130\u00CF\u1E2E\u1EC8\u01CF\u0208\u020A\u1ECA\u012E\u1E2C\u0197]/g},
    {'base':'J', 'letters':/[\u004A\u24BF\uFF2A\u0134\u0248]/g},
    {'base':'K', 'letters':/[\u004B\u24C0\uFF2B\u1E30\u01E8\u1E32\u0136\u1E34\u0198\u2C69\uA740\uA742\uA744\uA7A2]/g},
    {'base':'L', 'letters':/[\u004C\u24C1\uFF2C\u013F\u0139\u013D\u1E36\u1E38\u013B\u1E3C\u1E3A\u0141\u023D\u2C62\u2C60\uA748\uA746\uA780]/g},
    {'base':'LJ','letters':/[\u01C7]/g},
    {'base':'Lj','letters':/[\u01C8]/g},
    {'base':'M', 'letters':/[\u004D\u24C2\uFF2D\u1E3E\u1E40\u1E42\u2C6E\u019C]/g},
    {'base':'N', 'letters':/[\u004E\u24C3\uFF2E\u01F8\u0143\u00D1\u1E44\u0147\u1E46\u0145\u1E4A\u1E48\u0220\u019D\uA790\uA7A4]/g},
    {'base':'NJ','letters':/[\u01CA]/g},
    {'base':'Nj','letters':/[\u01CB]/g},
    {'base':'O', 'letters':/[\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]/g},
    {'base':'OI','letters':/[\u01A2]/g},
    {'base':'OO','letters':/[\uA74E]/g},
    {'base':'OU','letters':/[\u0222]/g},
    {'base':'P', 'letters':/[\u0050\u24C5\uFF30\u1E54\u1E56\u01A4\u2C63\uA750\uA752\uA754]/g},
    {'base':'Q', 'letters':/[\u0051\u24C6\uFF31\uA756\uA758\u024A]/g},
    {'base':'R', 'letters':/[\u0052\u24C7\uFF32\u0154\u1E58\u0158\u0210\u0212\u1E5A\u1E5C\u0156\u1E5E\u024C\u2C64\uA75A\uA7A6\uA782]/g},
    {'base':'S', 'letters':/[\u0053\u24C8\uFF33\u1E9E\u015A\u1E64\u015C\u1E60\u0160\u1E66\u1E62\u1E68\u0218\u015E\u2C7E\uA7A8\uA784]/g},
    {'base':'T', 'letters':/[\u0054\u24C9\uFF34\u1E6A\u0164\u1E6C\u021A\u0162\u1E70\u1E6E\u0166\u01AC\u01AE\u023E\uA786]/g},
    {'base':'TZ','letters':/[\uA728]/g},
    {'base':'U', 'letters':/[\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]/g},
    {'base':'V', 'letters':/[\u0056\u24CB\uFF36\u1E7C\u1E7E\u01B2\uA75E\u0245]/g},
    {'base':'VY','letters':/[\uA760]/g},
    {'base':'W', 'letters':/[\u0057\u24CC\uFF37\u1E80\u1E82\u0174\u1E86\u1E84\u1E88\u2C72]/g},
    {'base':'X', 'letters':/[\u0058\u24CD\uFF38\u1E8A\u1E8C]/g},
    {'base':'Y', 'letters':/[\u0059\u24CE\uFF39\u1EF2\u00DD\u0176\u1EF8\u0232\u1E8E\u0178\u1EF6\u1EF4\u01B3\u024E\u1EFE]/g},
    {'base':'Z', 'letters':/[\u005A\u24CF\uFF3A\u0179\u1E90\u017B\u017D\u1E92\u1E94\u01B5\u0224\u2C7F\u2C6B\uA762]/g},
    {'base':'a', 'letters':/[\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]/g},
    {'base':'aa','letters':/[\uA733]/g},
    {'base':'ae','letters':/[\u00E6\u01FD\u01E3]/g},
    {'base':'ao','letters':/[\uA735]/g},
    {'base':'au','letters':/[\uA737]/g},
    {'base':'av','letters':/[\uA739\uA73B]/g},
    {'base':'ay','letters':/[\uA73D]/g},
    {'base':'b', 'letters':/[\u0062\u24D1\uFF42\u1E03\u1E05\u1E07\u0180\u0183\u0253]/g},
    {'base':'c', 'letters':/[\u0063\u24D2\uFF43\u0107\u0109\u010B\u010D\u00E7\u1E09\u0188\u023C\uA73F\u2184]/g},
    {'base':'d', 'letters':/[\u0064\u24D3\uFF44\u1E0B\u010F\u1E0D\u1E11\u1E13\u1E0F\u0111\u018C\u0256\u0257\uA77A]/g},
    {'base':'dz','letters':/[\u01F3\u01C6]/g},
    {'base':'e', 'letters':/[\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]/g},
    {'base':'f', 'letters':/[\u0066\u24D5\uFF46\u1E1F\u0192\uA77C]/g},
    {'base':'g', 'letters':/[\u0067\u24D6\uFF47\u01F5\u011D\u1E21\u011F\u0121\u01E7\u0123\u01E5\u0260\uA7A1\u1D79\uA77F]/g},
    {'base':'h', 'letters':/[\u0068\u24D7\uFF48\u0125\u1E23\u1E27\u021F\u1E25\u1E29\u1E2B\u1E96\u0127\u2C68\u2C76\u0265]/g},
    {'base':'hv','letters':/[\u0195]/g},
    {'base':'i', 'letters':/[\u0069\u24D8\uFF49\u00EC\u00ED\u00EE\u0129\u012B\u012D\u00EF\u1E2F\u1EC9\u01D0\u0209\u020B\u1ECB\u012F\u1E2D\u0268\u0131]/g},
    {'base':'j', 'letters':/[\u006A\u24D9\uFF4A\u0135\u01F0\u0249]/g},
    {'base':'k', 'letters':/[\u006B\u24DA\uFF4B\u1E31\u01E9\u1E33\u0137\u1E35\u0199\u2C6A\uA741\uA743\uA745\uA7A3]/g},
    {'base':'l', 'letters':/[\u006C\u24DB\uFF4C\u0140\u013A\u013E\u1E37\u1E39\u013C\u1E3D\u1E3B\u017F\u0142\u019A\u026B\u2C61\uA749\uA781\uA747]/g},
    {'base':'lj','letters':/[\u01C9]/g},
    {'base':'m', 'letters':/[\u006D\u24DC\uFF4D\u1E3F\u1E41\u1E43\u0271\u026F]/g},
    {'base':'n', 'letters':/[\u006E\u24DD\uFF4E\u01F9\u0144\u00F1\u1E45\u0148\u1E47\u0146\u1E4B\u1E49\u019E\u0272\u0149\uA791\uA7A5]/g},
    {'base':'nj','letters':/[\u01CC]/g},
    {'base':'o', 'letters':/[\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]/g},
    {'base':'oi','letters':/[\u01A3]/g},
    {'base':'ou','letters':/[\u0223]/g},
    {'base':'oo','letters':/[\uA74F]/g},
    {'base':'p','letters':/[\u0070\u24DF\uFF50\u1E55\u1E57\u01A5\u1D7D\uA751\uA753\uA755]/g},
    {'base':'q','letters':/[\u0071\u24E0\uFF51\u024B\uA757\uA759]/g},
    {'base':'r','letters':/[\u0072\u24E1\uFF52\u0155\u1E59\u0159\u0211\u0213\u1E5B\u1E5D\u0157\u1E5F\u024D\u027D\uA75B\uA7A7\uA783]/g},
    {'base':'s','letters':/[\u0073\u24E2\uFF53\u00DF\u015B\u1E65\u015D\u1E61\u0161\u1E67\u1E63\u1E69\u0219\u015F\u023F\uA7A9\uA785\u1E9B]/g},
    {'base':'t','letters':/[\u0074\u24E3\uFF54\u1E6B\u1E97\u0165\u1E6D\u021B\u0163\u1E71\u1E6F\u0167\u01AD\u0288\u2C66\uA787]/g},
    {'base':'tz','letters':/[\uA729]/g},
    {'base':'u','letters':/[\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]/g},
    {'base':'v','letters':/[\u0076\u24E5\uFF56\u1E7D\u1E7F\u028B\uA75F\u028C]/g},
    {'base':'vy','letters':/[\uA761]/g},
    {'base':'w','letters':/[\u0077\u24E6\uFF57\u1E81\u1E83\u0175\u1E87\u1E85\u1E98\u1E89\u2C73]/g},
    {'base':'x','letters':/[\u0078\u24E7\uFF58\u1E8B\u1E8D]/g},
    {'base':'y','letters':/[\u0079\u24E8\uFF59\u1EF3\u00FD\u0177\u1EF9\u0233\u1E8F\u00FF\u1EF7\u1E99\u1EF5\u01B4\u024F\u1EFF]/g},
    {'base':'z','letters':/[\u007A\u24E9\uFF5A\u017A\u1E91\u017C\u017E\u1E93\u1E95\u01B6\u0225\u0240\u2C6C\uA763]/g}
];
var changes;
function removeDiacritics (str) {
    if(!changes) {
        changes = defaultDiacriticsRemovalMap;
    }
    for(var i=0; i<changes.length; i++) {
        str = str.replace(changes[i].letters, changes[i].base);
    }
    return str;
}

Answer 3

If you want to do it entirely on the client side, I think your only option is with some kind of lookup table. Here's a starting point, written by a chap called Olavi Ivask on his blog...

function replaceDiacritics(s)
{
    var s;

    var diacritics =[
        /[\300-\306]/g, /[\340-\346]/g,  // A, a
        /[\310-\313]/g, /[\350-\353]/g,  // E, e
        /[\314-\317]/g, /[\354-\357]/g,  // I, i
        /[\322-\330]/g, /[\362-\370]/g,  // O, o
        /[\331-\334]/g, /[\371-\374]/g,  // U, u
        /[\321]/g, /[\361]/g, // N, n
        /[\307]/g, /[\347]/g, // C, c
    ];

    var chars = ['A','a','E','e','I','i','O','o','U','u','N','n','C','c'];

    for (var i = 0; i < diacritics.length; i++)
    {
        s = s.replace(diacritics[i],chars[i]);
    }

    document.write(s);
}

You can see this is simply an array of regexes for known diacritic chars, mapping them back onto a "plain" character.

Answer 4

A simple modification to the script of Paul. Extend the String-object

String.prototype.removeDiacritics = function() {
    var diacritics = [
        [/[\300-\306]/g, 'A'],
        [/[\340-\346]/g, 'a'],
        [/[\310-\313]/g, 'E'],
        [/[\350-\353]/g, 'e'],
        [/[\314-\317]/g, 'I'],
        [/[\354-\357]/g, 'i'],
        [/[\322-\330]/g, 'O'],
        [/[\362-\370]/g, 'o'],
        [/[\331-\334]/g, 'U'],
        [/[\371-\374]/g, 'u'],
        [/[\321]/g, 'N'],
        [/[\361]/g, 'n'],
        [/[\307]/g, 'C'],
        [/[\347]/g, 'c'],
    ];
    var s = this;
    for (var i = 0; i < diacritics.length; i++) {
        s = s.replace(diacritics[i][0], diacritics[i][1]);
    }
    return s;
}

Now you can do:

var wrongString = "hëllô";
alert(wrongString.removeDiacritics()); // alerts "hello"

Answer 5

I have ported the Apache Lucene ASCII Folding Filter to JavaScript. You can replace a lot of Unicode characters (including diacritics) to ASCII base forms.

You can find the port on https://github.com/mplatt/fold-to-ascii-js

After integrating the library you could fold strings like that:

//foldToASCII("ăşţ"); -> depreciated

Edit

What I did to get this to work was follow the install instructions in his link then import the lib, and then I could use it.

import ASCIIFolder from fold-to-ascii

//Then I can call the following:
ASCIIFolder.foldReplacing("Lörem  ëripuît") === "Lorem  eripuit";

//Which results in `ast`.

Answer 6

Consider following syntax, where each symbol from value will be replaced with it's key symbol (case-sensitive)

var diacritics = {
  a: 'ÀÁÂÃÄÅàáâãäåĀāąĄ',
  c: 'ÇçćĆčČ',
  d: 'đĐďĎ',
  e: 'ÈÉÊËèéêëěĚĒēęĘ',
  i: 'ÌÍÎÏìíîïĪī',
  l: 'łŁ',
  n: 'ÑñňŇńŃ',
  o: 'ÒÓÔÕÕÖØòóôõöøŌō',
  r: 'řŘ',
  s: 'ŠšśŚ',
  t: 'ťŤ',
  u: 'ÙÚÛÜùúûüůŮŪū',
  y: 'ŸÿýÝ',
  z: 'ŽžżŻźŹ'
}

function replaceDiacritics(text) {
  for(var toLetter in diacritics) if(diacritics.hasOwnProperty(toLetter)) {
    for(var i = 0, ii = diacritics[toLetter].length, fromLetter, toCaseLetter; i < ii; i++) {
      fromLetter = diacritics[toLetter][i];
      if(text.indexOf(fromLetter) < 0) continue;
      toCaseLetter = fromLetter == fromLetter.toUpperCase() ? toLetter.toUpperCase() : toLetter;
      text = text.replace(new RegExp(fromLetter, 'g'), toCaseLetter);
    }
  }
  return text;
}

replaceDiacritics('ŁÁŘŠÓÑ'); // LARSON
replaceDiacritics('Łąřśøń'); // Larson

Answer 7

You would need a conversion map, something like this:

function removeAccents(str) {
    var convMap = {
        "ă" : "a",
        "ş" : "s",
        "ţ" : "t"
    }
    for (var i in convMap) {
        str = str.replace(new RegExp(i, "g"), convMap[i]);
    }
    return str;
}

Or if you have access to iconv on your box, you could perhaps use some ajax calls to remove the accents with iconv's //TRANSLIT parameter.

Answer 8

Here is ES2020 version of the accepted low-level solution. If You can recall the letters that need to be replaced, create a mapping and use String.replace() to map letters one-by-one:

const mapping = {
  'ă': 'a',
  'ş': 's',
  'ţ': 't'
}

const replaceDiacritics = s => s.split('').map(letter => mapping[letter] ?? letter).join('')

Answer 9

This method is a refactor of the first response.

function replaceDiacritics(str){

  var diacritics = [
    {char: 'A', base: /[\300-\306]/g},
    {char: 'a', base: /[\340-\346]/g},
    {char: 'E', base: /[\310-\313]/g},
    {char: 'e', base: /[\350-\353]/g},
    {char: 'I', base: /[\314-\317]/g},
    {char: 'i', base: /[\354-\357]/g},
    {char: 'O', base: /[\322-\330]/g},
    {char: 'o', base: /[\362-\370]/g},
    {char: 'U', base: /[\331-\334]/g},
    {char: 'u', base: /[\371-\374]/g},
    {char: 'N', base: /[\321]/g},
    {char: 'n', base: /[\361]/g},
    {char: 'C', base: /[\307]/g},
    {char: 'c', base: /[\347]/g}
  ]

  diacritics.forEach(function(letter){
    str = str.replace(letter.base, letter.char);
  });

  return str;
};

Answer 10

Try this.

function replaceDiacritics(text) {     
  const diacr =     "ÁÄČÇĎÉĚËÍŇÓÖŘŠŤÚŮÜÝŽáäčçďéěëíňóöřšťúůüýž";
  const diacrSubs = "AACCDEEEINOORSTUUUYZaaccdeeeinoorstuuuyz";

  if (text.length < diacr.length) {
    for (let i = 0; i < text.length; i++) {
      let indexOfSpecChar = diacr.indexOf(text[i]);

      if (indexOfSpecChar > -1) {
        text = text.replace(new RegExp(diacr[indexOfSpecChar], 'g'), diacrSubs[indexOfSpecChar]);
      }

    }
  } else {
    for (let j = 0; j < diacr.length; j++) {
      text = text.replace(new RegExp(diacr[j], 'g'), diacrSubs[j]);
    }
  }

  return text;
}

Answer 11

const clean = (text) => {
  return text
    .toLocaleLowerCase("tr")
    .replace(/ı/g, "i")
    .normalize("NFKD")
    .replace(/[^\w]/g, "")
    .normalize("NFKD")
    .replace(/[^\w\s.-_/]/g, "")
    .replace(/[\uE000-\uF8FF]/g, "")
    .replace(/_/g, "");
};