Azure Cosmos Graph nest edge vertex in a vertex property - azure-cosmosdb

Question

I have two vertex:
1) Vertex 1: { id: 1, name: “john” }
2) Vertex 2: { id: 2, name: “mary” }
There is an edge from 1 to 2 named “children”.
Is it possible to return 2 nested in 1 using gremlin like this?
{
id: 1,
name: “john”,
children: { id: 2, name: “mary” }
}
Thank you!
My solution with an amazing help of #noam621 ---------------------------------
g.V(1)
.union( valueMap(true),
project('children').by( coalesce( out('children').valueMap(true).fold() , constant([]))),
project('parents').by( coalesce( out('parents').valueMap(true).fold() , constant([])))
)
.unfold().group().by(keys).by(select(values))
It returns the following object:
{
id: 1,
name: [ “john” ],
children: [ { id: 2, name: [ “mary” ] } ],
parents: []
}
.union with project are the key to merge all objects in one object.
valueMap(true).fold() is fundamental to get all objects in the edge and coalesce helps with a default value if the edge doesn't return any vertex.
Due to some Azure Cosmos gremlin limitations is only possible to get values as array values.
Thus I finalized the object formatting in my application code. It's ok for now.
Thank you!

Answer 1

You can do it by using the project step for both vertexes:
g.V(1).project('id', 'name', 'children').
by(id).
by('name').
by(out('children').
project('id', 'name').by(id).
by('name'))
example:
https://gremlify.com/3j
query with valueMap:
g.V(1).union(
valueMap().
with(WithOptions.tokens).by(unfold()),
project('children').
by(out('children').
valueMap().
with(WithOptions.tokens).by(unfold()))
).unfold().
group().by(keys).
by(select(values))
if valueMap().with(WithOptions.tokens) not supported in Cosmos use valueMap(true) instead