AddCustomFields add custom filed to json object.

CopyExcept copies all fields except fields with given names.

MarshalWithCustomFields marshals value merged with custom fields defined in the map into JSON bytes.

MergeCustomFields converts value to the JSON-like map and merges it with custom fields map cf.

Select copies only fields with given names.

ShallowCopyObj creates new json object with copied fields form provided object.

SplitJSONObj splits provides fields into separate object.

ToMap convert object, string or bytes to json object represented by map.

UnmarshalWithCustomFields unmarshals JSON into value v and puts all JSON fields which do not belong to value into custom fields map cf.