I just thought about how best to add metadata to for instance object keys in JSON.
For instance as I'm engineering an Open Source temporal document store, I'm storing some metadata in the binary encoding for each node. Optionally SirixDB for instance stores the number of descendants of objects, object keys and arrays, it optionally stores hash-codes for integrity checks and speeding up diff-computations and so on. Furthermore it would be great to be able to serialize the unique, stable 64 bit integer node identifiers.
Now, I want to serialize this additional data into the serialized JSON format. In the XML serialization I simply added attributes in a special namespace for the elements.
However, how would you serialize this stuff in a JSON document?