title: Three periods syntax in Vuex?
body: <p>I'm not solid on what mapstate does, other than that, what would ... mean in front of it. I don't see this nowhere as much within the guide as in example repos.</p>
  
  <pre><code>computed: {
    ...mapState({
      messages: state =&gt; state.messages
    })
  }
  </code></pre>