Enumerating on collections via forEach should be implicitly safe to mutations

When you are in a write transaction and enumerate on a collection, this should implicitly take place on a snapshot, so that it is safe to making mutations while enumerating. Otherwise objects would be removed when they aren’t matching the query anymore. e.g.

let dogs = realm.objects("Dog").filtered("age < 5");
dogs.forEach((dog) => {
  dog.age = 6;
});

Given this query would contain two instances, this would fail in the second call of the enumeration block, because the first instance wouldn’t match the query anymore.

/c @alazier @kristiandupont

[kneth]

@Udbhav12 snapshot() doesn’t copy any data but you are keeping a particular version of the database (Realm is MVCC) so it will have an impact on memory and the size of the Realm file.

[kneth]

snapshot() was introduce to solve this problem. You can also use the property isValid on an object to see if it is safe to access it.