AppSync graphql query not returning expected data - graphql

Question

I have an AppSync graphql schema with Users and Events, that should have a bi-directional connection. My schema looks like this:
type User #model {
id: ID!
email: String
events: [EventUser] #connection(name: "EventUser", keyName: "byUser", fields: ["id"])
}
type Event #model {
id: ID!
name: String
description: String
registeredUsers: [EventUser] #connection(name: "EventUser", keyName: "byEvent", fields: ["id"])
invitedUsers: [User]
}
type EventUser
#model(queries: null)
#key(name: "byEvent", fields: ["eventId", "userId"])
#key(name: "byUser", fields: ["userId", "eventId"]) {
id: ID!
eventId: ID!
userId: ID!
event: Event! #connection(fields: ["eventId"])
user: User! #connection(fields: ["userId"])
}
The query that is generated by the CLI looks like this:
export const listEvents = /* GraphQL */ `
query ListEvents(
$filter: ModelEventFilterInput
$limit: Int
$nextToken: String
) {
listEvents(filter: $filter, limit: $limit, nextToken: $nextToken) {
items {
id
name
description
registeredUsers {
nextToken
}
createdAt
updatedAt
}
nextToken
}
}
`;
When I run this query with:
const result = await API.graphql(graphqlOperation(queries.listEvents, { limit: 10}))
I get these results:
[
{
"createdAt": "2020-08-17T21:36:04.502Z",
"description": "Event description",
"id": "some-unique-id",
"name": "Event name",
"registeredUsers": Object {
"nextToken": null,
},
"updatedAt": "2020-08-17T21:36:04.502Z",
},
{
"createdAt": "2020-08-17T21:36:04.502Z",
"id": "some-other-unique-id",
"name": "event 2 name",
"registeredUsers": Object {
"nextToken": null, // <- This seems wrong.
},
"updatedAt": "2020-08-17T21:36:04.502Z"
}
]
The registeredUsers field should be an array of items. I can run a query in the AppSync console like this:
query ListEvents {
listEvents( limit: 10) {
items {
id
name
registeredUsers {
items {
userId
}
}
}
}
}
and it returns correct results:
{
"data": {
"listEvents": {
"items": [
{
"id": "some-unique-id",
"name": "event name",
"registeredUsers": {
"items": [
{
"userId": "user"
},
{
"userId": "user1"
}
]
}
},
{
"id": "some-other-unique-id",
"name": "event 2 name",
"registeredUsers": {
"items": []
}
},
]
}
}
}
Obviously, the console query is slightly different but it produces correct results, although it does not handle nextToken pagination.
My question is this: Is the CLI-generated query invalid? If so, is it because my Schema is not set up correctly?
If the generated query is valid, how would I call it to get the EventUser data?