polybius.fyi/reveal.js/node_modules/underscore.string/cleanDiacritics.js

var makeString = require('./helper/makeString');

var from  = "ąàáäâãåæăćčĉęèéëêĝĥìíïîĵłľńňòóöőôõðøśșşšŝťțţŭùúüűûñÿýçżźž",
    to    = "aaaaaaaaaccceeeeeghiiiijllnnoooooooossssstttuuuuuunyyczzz";

from += from.toUpperCase();
to += to.toUpperCase();

to = to.split("");

// for tokens requireing multitoken output
from += "ß";
to.push('ss');


module.exports = function cleanDiacritics(str) {
    return makeString(str).replace(/.{1}/g, function(c){
      var index = from.indexOf(c);
      return index === -1 ? c : to[index];
  });
};