Typescript error joining on an optional field with `eq`.

[thruflo]

I have event and user collections defined with the following (abbreviated) zod schemas:

const userSchema = z.object({
  id: z.uuid()
})

const eventSchema = z.object({
  user_id: z.uuid().optional()
})

If I try to do an inner join between them like this:

query
  .from({ event: eventCollection })
  .innerJoin(
    { user: userCollection },
    ({ event, user }) => eq(event.user_id, user.id)
  )

I get a typescript error:

No overload matches this call.
  Overload 1 of 3, '(left: RefProxy<string | undefined>, right: string | RefProxy<string | undefined> | BasicExpression<string | undefined> | undefined): BasicExpression<...>', gave the following error.
    Argument of type 'RefProxy<string | undefined> | undefined' is not assignable to parameter of type 'RefProxy<string | undefined>'.
      Type 'undefined' is not assignable to type 'RefProxy<string | undefined>'.
  Overload 2 of 3, '(left: string | number | boolean | BasicExpression<string | number | boolean>, right: string | number | boolean | BasicExpression<string | number | boolean>): BasicExpression<...>', gave the following error.
    Argument of type 'RefProxy<string | undefined> | undefined' is not assignable to parameter of type 'string | number | boolean | BasicExpression<string | number | boolean>'.
      Type 'undefined' is not assignable to type 'string | number | boolean | BasicExpression<string | number | boolean>'.
  Overload 3 of 3, '(left: Aggregate<unknown>, right: any): BasicExpression<boolean>', gave the following error.
    Argument of type 'RefProxy<string | undefined> | undefined' is not assignable to parameter of type 'Aggregate<unknown>'.
      Type 'undefined' is not assignable to type 'Aggregate<unknown>'.

         .innerJoin({ user: userCollection }, ({ event, user }) => eq(event.user_id, user.id))

If I swap the order of the arguments to eq then I don't get the error. Is this correct / expected? Or should eq handle optional fields as the first argument in this situation?

[samwillis]

This is a bug, it should handle it on both sides.