discourse/app/assets/javascripts/discourse/lib/censored-words.js

Discourse.CensoredWords = {
  censor: function(text) {
    var censorRegexp,
        censored = Discourse.SiteSettings.censored_words;

    if (censored && censored.length) {
      if (!censorRegexp) {
        var split = censored.split("|");
        if (split && split.length) {
          censorRegexp = new RegExp("\\b(?:" + split.map(function (t) { return "(" + t.replace(/[-/\\^$*+?.()|[\]{}]/g, '\\$&') + ")"; }).join("|") + ")\\b", "ig");
        }
      }
      if (censorRegexp) {
        var m = censorRegexp.exec(text);
        while (m && m[0]) {
          var replacement = new Array(m[0].length+1).join('■');
          text = text.replace(new RegExp("\\b" + m[0] + "\\b", "ig"), replacement);
          m = censorRegexp.exec(text);
        }

      }
    }
    return text;
  }
};