Vuex getters in computed properties showing undefined until full page load

I'm trying to create computed properties using data pulled with the mapGetters function in vuex, but I'm always getting undefined, until the page/dom fully loads.

Here's an example for an isRegistered computed property that I use to hide/display certain buttons.

computed: {
      ...mapGetters(['solos', 'user']),
      isRegistered () {
        return this.solos.registered.indexOf(this.user._id) !== -1
      }
}

Here is the HTML for buttons that use the isRegistered computed property.

<a href="#" class="register-button" v-if="!isRegistered">REGISTER NOW</a>
<a href="#" class="registered-button" v-if="isRegistered">REGISTERED</a>

I'm setting the getters via an action which I'm calling in the created function

created () {
      this.getTournament('solos').catch(err => {})
}

Here's my action for setting the corresponding getters

getTournament: ({commit}, type) => {
    return feathers.service('tournaments').find({
      query: {
        type: type,
        status: 'registering'
      }
    }).then(tourney => {
      commit(type.toUpperCase(), tourney.data[0])
    })
}

Here's the corresponding mutation

const mutations = {
  SOLOS (state, result) {
    state.solos = result;
  }
};

Here's the corresponding getter

const getters = {
   solos (state) {
     return state.solos
   }
}

The issue I'm having is the value is initially showed as undefined until the PAGE/DOM is fully loaded, causing .indexOf to throw the following error:

TypeError: Cannot read property 'indexOf' of undefined

The only way I've been able to get this to work is to use an if statement on the computed property that checks if the state data has loaded yet.

isRegistered () {
  if (this.solos._id) return this.solos.registered.indexOf(this.user._id) !== -1
}

This doesn't seem like a proper way of doing things. What am I doing wrong?