code: function serializeProperty(metadata, prop) {
      if (!metadata || metadata.excludeToJson === true) {
          return;
      }
      if (metadata.customConverter) {
          return metadata.customConverter.toJson(prop);
      }
      if (!metadata.clazz) {
          return prop;
      }
      if (utils_1.isArrayOrArrayClass(prop)) {
          return prop.map(function (propItem) { return serialize(propItem); });
      }
      return serialize(prop);
  }
docs: Prepare a single property to be serialized to JSON.
  
  @param metadata
  @param prop
  @returns {any}