code: function (target, key) {
      var metadata = getJsonPropertyDecoratorMetadata(target, key);
      // tslint:disable-next-line:triple-equals
      if (metadata != undefined && metadata.name != undefined) {
          return metadata.name;
      }
      else {
          return key;
      }
  }
docs: Returns the JsonProperty name (if any) associated with the object instance.
  If any JsonProperty metadata found, it returns the key name as the name of the property.