https://github.com/linkedin/dustjs/blob/c20e70edb2041a66067a010bdefbf9fe3267c7ab/lib/dust.js

dust.js

var HCHARS = /[&<>"']/,
      AMP    = /&/g,
      LT     = /</g,
      GT     = />/g,
      QUOT   = /\"/g,
      SQUOT  = /\'/g;

dust.escapeHtml = function(s) {
if (typeof s === 'string') {
  if (!HCHARS.test(s)) {
    return s;
  }
  return s.replace(AMP,'&amp;').replace(LT,'&lt;').replace(GT,'&gt;').replace(QUOT,'&quot;').replace(SQUOT, '&#39;');
}
return s;
};