code: function (item) {                                                                            // 233
    for (var i = 0; i < builtinConverters.length; i++) {                                                               // 234
      var converter = builtinConverters[i];                                                                            // 235
      if (converter.matchObject(item)) {                                                                               // 236
        return converter.toJSONValue(item);                                                                            // 237
      }                                                                                                                // 238
    }                                                                                                                  // 239
    return undefined;                                                                                                  // 240
  }
docs: 229 230 Either return the JSON-compatible version of the argument, or undefined (if                                       // 231 the item isn't itself replaceable, but maybe some fields in it are)                                               // 232