title: Existing component throw: Unknown custom element
body: <p>I'm trying to use a component in another component. On the <code>created</code> event, I can log this component and it returns the good object. However for some reasons, the component doesn't seem to be included. VueJS do not understand the <code>validation</code> tag.</p>
  
  <p>Any ideas?</p>
  
  <pre><code>&lt;template&gt;
    &lt;main&gt;
      &lt;validation :validate="$v.email" :model="'email'"&gt;&lt;/validation&gt; 
    &lt;/main&gt;
  &lt;/template&gt;
  &lt;script&gt;
    import { Validation } from 'components/helpers'
  
    export default {
      name: 'login',
      component: { Validation },
      created() {
        // it works. print the component with his path
        window.console.log(Validation)
      }
    }
  &lt;/script&gt;
  </code></pre>
  
  <blockquote>
    <p>[Vue warn]: Unknown custom element:  - did you register
    the component correctly? For recursive components, make sure to
    provide the "name" option.</p>
  </blockquote>
  
  <p>In <code>components/helpers</code> I have two file:</p>
  
  <p>1) index.js</p>
  
  <pre><code>export { default as Validation } from './Validation'
  </code></pre>
  
  <p>2) Validation.vue</p>
  
  <pre><code>&lt;template&gt;
      &lt;div&gt;
          &lt;span class="form__validation" v-if="validate &amp;&amp; !validate.required"&gt;Required&lt;/span&gt;
          &lt;template v-if="validation[model]"&gt;
              &lt;span class="form__validation" v-for="error in validation[model].messages"&gt;{{ error }}&lt;/span&gt;
          &lt;/template&gt;
      &lt;/div&gt;
  &lt;/template&gt;
  
  &lt;script&gt;
  import { mapGetters } from 'vuex'
  
  export default {
    name: 'validation',
    data() {
      return {
        L: L
      }
    },
    props: ['model', 'validate'],
    computed: {
      ...mapGetters({
        validation: 'getValidation'
      })
    }
  }
  &lt;/script&gt;
  </code></pre>