In it’s basic form, JSON cannot serialize cyclic graphs of objects, or graphs where multiple paths can lead to the same object. In a project I’m working on, I wanted to move such a graph of highly-interconnected objects from JS to python. So I have invented a format built on top of JSON that can be used to serialize/deserialize such graphs.

Basically, the JSON comes across as a large list:

[
  /* list[0] is the base object at the root of the eventual object graph. */
  {
    /* string, number, true/false, and null properties are serialized directly */
    "stringprop": "stringvalue",
    "numprop": 3.1415,
    /* but lists and objects are not serialized directly. Instead, they are represented by an index
       into the base list. "sharp" is a nod to JS sharp variables, from which this was originally inspired */
    "complexprop": {"sharp": 1}
  },
  /* list[1] is referenced from list[0].complexprop. It also references itself, see below */
  [
    "simplestring",
    3,
    {"sharp": 1}
  ]
]

You can find JS for serializing these types of graphs here, and python for deserializing them here.

It turns out that I probably don’t actually need this code: I’ve found a simpler solution for my particular problem, but I wanted to share this solution in case other people might find it useful.