function clearNonPrintableCharacter(str) {
  var str2 = "";
  for (var i = 0, len = str.length; i < len; i++) {
    str2 += str.charCodeAt(i) < 32 ? " " : str.charAt(i);
  }
  return _.trim(str2);
}
clear nonprintable characters

@param {String} str
@return {String}