title: Why is computed value not updated after vuex store update?
body: <p>I got a <code>printerList</code> computed property that should be re-evaluated after <code>getPrinters()</code> resolve, but it look like it's not.</p>
  
  <p><a href="https://github.com/Coaxis-ASP/opt/tree/f1267a6a4f1202a3db710b1ee0639996730186c1/frontend/src" rel="noreferrer">sources are online</a>: <a href="https://github.com/Coaxis-ASP/opt/blob/f1267a6a4f1202a3db710b1ee0639996730186c1/frontend/src/pages/optboxes/optbox.component.vue" rel="noreferrer">optbox.component.vue</a>, <a href="https://github.com/Coaxis-ASP/opt/tree/f1267a6a4f1202a3db710b1ee0639996730186c1/frontend/src/vuex" rel="noreferrer">vuex</a>, <a href="https://github.com/Coaxis-ASP/opt/blob/f1267a6a4f1202a3db710b1ee0639996730186c1/frontend/src/services/optboxes.service.js" rel="noreferrer">optboxes.service.js</a></p>
  
  <h3>Component</h3>
  
  <pre><code>&lt;template&gt;
      &lt;div v-for="printer in printersList"&gt;
          &lt;printer :printer="printer" :optbox="optbox"&gt;&lt;/printer&gt;
      &lt;/div&gt;
  &lt;/template&gt;
  &lt;script&gt;
  …
  created() { this.getPrinters(this.optbox.id); },
      computed: {
          printersList() {
              var index = optboxesService.getIndex(this.optboxesList, this.optbox.id);
              return this.optboxesList[index].printers
          }
      },
      vuex: {
          actions: { getPrinters: actions.getPrinters,},
          getters: { optboxesList: getters.retrieveOptboxes}
      }
  &lt;script&gt;
  </code></pre>
  
  <h3>Actions</h3>
  
  <pre><code>getPrinters({dispatch}, optboxId) {
      printers.get({optbox_id: optboxId}).then(response =&gt; {
          dispatch('setPrinters', response.data.optbox, response.data.output.channels);
      }).catch((err) =&gt; {
          console.error(err);
          logging.error(this.$t('printers.get.failed'))
      });
  },
  </code></pre>
  
  <h3>Mutations</h3>
  
  <pre><code>setPrinters(optboxes, optboxId, printers) {
      var index = this.getIndex(optboxes, optboxId);
      optboxes[index] = {...optboxes[index], printers: printers }
  },
  </code></pre>
  
  <h3>Question</h3>
  
  <p>Why does the <code>printerList</code> computed property isn't re-evaluated (i.e. the <code>v-for</code> is empty)</p>