[Vuejs]-Manipulating documents in Firebase collection with Vuex [Vuex/Vuexfire]

As you will see in the Vuexfire documentation:

Vuexfire does not handle writing data back to Firebase because you can
directly use the Firebase JS SDK to precisely update whatever you
need.

The doc gives some example of use of the “standard” JS SDK, exactly like you did in your question (“classic firebase command”). So you’ll have to go this way, wrapping the database writes in Vuex Actions.