On graphs, I was really hoping to see provisions in the spec to support the property graph model, specifically for properties on relationships. We are building APIs that access data in a graph DB, and all the data in the graph has had an obvious representation in the JSON API model except for attributes on edges.

As an example, let's say that my graph DB has People nodes and a MARRIED_TO relationship between two people to indicate they are married. A MARRIED_TO edge could have a "married_on" property containing the date of the marriage.

Where would the "married_on" attribute be represented in JSON API? I could stuff it in the "meta" member of the link object, but that feels loose and hacky. Maybe it could live in the "linkage object" along with the "type" and "id" members. But the linkage object appears to currently be a closed set of only those two members.

Is this requirement to present a full property graph model not as common as I would imagine? I'm a bit behind on my sync with the current state of the spec. This is the first time I've tried to elaborate this need.