I believe it's not automatic, you have to tell which fields you want converted, see https://mesqueeb.github.io/vuex-easy-firestore/extra-features.html#firestore-timestamp-conversion

As a side note, if you ever want to persist the state locally using vuex-persist for example, I would advise against having a Date object in it (or any other non-flat object, like functions for example), because the state will not be serializable (or maybe not as you'd expect). Better take the habit now to deal with timestamps.

@louisameline - Thank you for the response. It's ok to work with .toDate() but I thought created_at and updated_at are transformed automatically to a date object before adding them to the local store according the documentation?

I have tested again. Even if explained in the documentation, the transformation is not done automatically for created_at and updated_at. But it works when I configure it manually as described.

So - is there any reason for that behavior that it's not done by default?

You're right, I hadn't noticed that.

I'll let @mesqueeb answer if it was his intention, but I must say that in my opinion, if the fields are currently not converted by default, it needs to stay that way, and it's the documentation which needs to be updated. And if they are converted, we should change that in v2 as by default, the state should not be tampered with.
In my experience, I've almost always regretted "automagic" which is supposed to help the user (but it's great to have options you can enable!). I think having a local state identical to the remote state by default is less prone to confusion. And again, the state needs to be serializable for some people.

Ok, now it's clear to me. So it would be good to have the updated documentation :-)

@scriptPilot It fell through the cracks 😆 I'll update the docs.