discourse/app/assets/javascripts/locales/cs.js.erb

//= depend_on 'client.cs.yml'
//= require locales/i18n
<%= JsLocaleHelper.output_locale(:cs) %>

I18n.pluralizationRules['cs'] = function (n) {
  if (n == 0) return ["zero", "none", "other"];
  if (n == 1) return "one";
  if (n >= 2 && n <= 4) return "few";
  return "other";
};