Filtering nested tree of document in Fauna db?

Question

I have following data structure of a single document in Fauna:

"data": {
 "title": "Title1",
 "blocks": [
  { 
    "block_1": {
     "text": "Text1",
     "refs": Ref(Collection("xyz"), "XYZ") 
  },
  { 
    "block_2": {
     "text": "Text2",
     "refs": Ref(Collection("xyz"), "XYZ2") 
  }
 ]
}

Say that the document is given. Is there a way in FQL to get the “blocks” based on their “refs” value? E.g. only return “block_1” based on “refs” = XYZ. I.e. the above example should only return “block_1”.

I hope the question is clear. Feel free to ask for clarification. :slight_smile:

Thanks for your help.

Answer 1

Let({
  blocks: Select(["data", "blocks"], Get(Ref(Collection("Blocks"), "299664869783765505"))),
  entitiesArray: Map(Var("blocks"), block => ToArray(block)),
  entities: Reduce((acc,value) => Append(acc, value) ,[],Var("entitiesArray")),
  find: Filter(Var("entities"), entity => Equals(Select([1, "refs"], entity), Ref(Collection("xyz"), "1")))
}, 
ToObject(Var("find"))
)

But I would suggest revising the blocks structure. Try to keep it as an array

"blocks": [
  {"text": "Text1", "refs": Ref(Collection("xyz"), 1) }, 
  {"text": "Text2", "refs": Ref(Collection("xyz"), 2) }
]

So FQL would be

Let({
  blocks: Select(["data", "blocks"], Get(Ref(Collection("Blocks"), "299664869783765505"))),
  find: Filter(Var("blocks"), entity => Equals(Select(["refs"], entity), Ref(Collection("xyz"), "1")))
}, 
Var("find")
)

Or an object

"blocks": {
  "block_1": {
    "text": "Text1",
    "refs": Ref(Collection("xyz"), 1) 
   },
   "block_2": {
     "text": "Text2",
     "refs": Ref(Collection("xyz"), 2) 
   }
}

FQL

Let({
  blocks: Select(["data", "blocks"], Get(Ref(Collection("Blocks"), "299664869783765505"))),
  entities: ToArray(Var("blocks")),
  find: Filter(Var("entities"), entity => Equals(Select([1,"refs"], entity), Ref(Collection("xyz"), "1")))
}, 
ToObject(Var("find"))
)