"include" query returning empty array when accessing field

[Jaime02]

Describe the bug
I am trying to use an include subquery in my query.
The query seems to work fine, console.log shows that the productionOrder[0] has the part array (it is a 1:1 relation but currently using toArray is the only way of materializing includes) with the correct part found, but when I access the productionOrders[0].part to get the array (then I will access the part[0] to get the part), it is empty, this should be impossible, it does not make any sense 🤯🤯🤯

To Reproduce

1. Create a Live Query with an include, a 1:1 relation. In my case:

export function useQueryProductionOrderTable() {
  return useLiveQuery((q) =>
    q.from({ productionOrder: productionOrderCollection }).select(({ productionOrder }) => ({
      ...productionOrder,
      ...
      part: toArray(
        q
          .from({ part: partCollection })
          .where(({ part }) => eq(part.id, productionOrder.partId))
          .select(({ part }) => ({
            ...part,
            shape: toArray(q.from({ shape: shapeCollection }).where(({ shape }) => eq(shape.id, part.shapeId))),
            ),
            ...
          })),
      ),
     ...
    })),
  );
}

2. Execute query

const { data: productionOrders } = useQueryProductionOrderTable();
console.log("productionOrders[0]:", productionOrders[0]); // This shows that there is a "part" attribute which is an array WITH 1 ELEMENT
console.log("productionOrders[0].part:", productionOrders[0]?.part);  // THIS LOGS AN EMPTY ARRAY ????????

Expected behavior
The query should return the linked part to the productionOrder properly due to the toArray call to materialize the collection instance

Screenshots

• Device: [e.g. iPhone6]
• OS: Windows
• Browser: Brave
• Version
  @tanstack/electric-db-collection: 0.3.3
  @tanstack/react-db: 0.1.83

STACKBLITZ REPRODUCIBLE EXAMPLE:
https://stackblitz.com/~/github.com/Jaime02/tanstack-db-query-include

I guess that toArray return type should include undefined because that is what is returned while the included collection is loading

[Jaime02]

I think that the query loads the included collections in an "asynchronously" way, so the fields' value is initially undefined ... They are eventually materialized.

I have found two temporal patches:

1. Wait until query's isLoading becomes false before accessing the included fields
2. Fill the codebase with safe optional chaining operator (?.), e.g.: productionOrders.at(0)?.part?.at(0)?.description. This shows a type error because the query return data type does not include undefined, e.g.:

const productionOrders: {
    id: number;
    partId: number;
    ...
    part: WithVirtualProps<{
        id: number;
        description: string;
        ...
    }, string | number>[];
    ...;
}[]

(Note that this method causes waterfall loading)
Finally, note that this issue is causing a lot of re-renders since the query data changes every time an included collection's data is materialized 😵‍💫