the result from useQuery is not usable in adding subscriptions.

[sync-by-unito]

No description provided.

[sync-by-unito]

➤ On 2022-03-24, Kenneth Geisshirt commented:

We need to include FLX support as a requirement for sync support of Realm React: https://jira.mongodb.org/browse/RJS-1517

[tomduncalf]

It seems that the way React Native implements ES6 Proxy is not compatible with how our is_instance function works. is_instance calls has_instance, which calls the JSC JSValueIsObjectOfClass function.

This function should handle Proxy instances by looking at the proxy target, but this doesn't work with React Native – this can be tested by wrapping a Results instance in a Proxy, entirely bypassing Realm React, and passing it to MutableSubscriptions::add – it will fail on React Native.

This works as expected on Node (which is obviously a different runtime) and on Hermes.

[tomduncalf]

Closing in favour of waiting for v11 to be released which uses JSI and will fix the fundamental Proxy issue. Workaround for now is to pass in the results directly, e.g.

const people = useQuery(realm.objects('Person'));
// ...
realm.subscriptions.update(subs => {
  subs.add(people); // this will error
});

becomes

const results = realm.objects('Person');
const people = useQuery(people);
// ...
realm.subscriptions.update(subs => {
  subs.add(results); // no error as we are passing in the Realm.Results instance directly
});

[tomduncalf]

We have decided to implement this workaround