I used the code example from the official RTK query documentation

CodePudding user response：

Entity adapter default expects the entity to have id for unique identification. In your case, as i can see, unique id of the user id named as _id.

Try the following way of explicitly setting the id:

const usersAdapter = createEntityAdapter({
  selectId: (user) => user._id,
});

Hopefully, that should fix the issue.

Thanks.