Join tables with concatMap

Question

r.table('users').hasFields('name').concatMap(function(user) {
    return r.table("bets").getAll(
        user('userID'),
        { index: "userID" }
    ).map(function(bet) {
        return { left: user, right: bet }
    })
})

Goal: Read all users and their bets. All bets should be in an array.

{
  "left": {
    "name": "Eki95",
    "userID": "525dc15b-ebde-464b-a936-bab4ed7e4965"
  },
  "right": [{
    "id": "4987c183-edc1-4cd0-9c8d-f51357b86908",
    "bet": "foo",
    "userID": "525dc15b-ebde-464b-a936-bab4ed7e4965",
  },
  {
    "id": "18e95569-107f-4182-85c1-7df269880978",
    "bet": "bar",
    "userID": "525dc15b-ebde-464b-a936-bab4ed7e4965",
  },
  ]
}

What I actually get:

{
  "left": {
    "name": "Eki95",
    "userID": "525dc15b-ebde-464b-a936-bab4ed7e4965"
  },
  "right": {
    "bet": "foo",
    "id": "4987c183-edc1-4cd0-9c8d-f51357b86908",
    "userID": "525dc15b-ebde-464b-a936-bab4ed7e4965",
  }
},


{
  "left": {
    "name": "Eki95",
    "userID": "525dc15b-ebde-464b-a936-bab4ed7e4965"
  },
  "right": {
    "bet": "bar",
    "id": "18e95569-107f-4182-85c1-7df269880978",
    "userID": "525dc15b-ebde-464b-a936-bab4ed7e4965",
  }
},

I could get my result by looping all entries, which is kind of a pain. Is there any way to do this with a query in rethinkdb?

Answer 1

Thanks to https://stackoverflow.com/users/3200554/mlucy, I could get it working:

r.table('users').hasFields('name').map(function(user) {
    return {
        user: user,
        bets: r.table('bets').getAll(user('userID'), {index: 'userID'}).coerceTo('array'),
    };
}

I had to adjust the query a bit and add coerceTo('array') because otherwise it would have thrown a

ReqlQueryLogicError: Expected type DATUM but found SELECTION

exception.