title: Cannot read property 'indexOf' of undefined when using Vue Carousel
body: <p>I'm using the latest version of Vue Carousel in my Nuxt JS application. It seems that I get errors on each of my blog posts whenever using the <code>universal</code> mode for Nuxt JS. If I take out Vue Carousel and do a standard <code>v-for</code> loop, the blogs show perfectly fine, there's something causing the error when using the carousel.</p>
  
  <p>My code:</p>
  
  <pre><code>&lt;carousel :paginationEnabled="false" :navigationEnabled="true" :perPageCustom="[[250, 1], [1024, 2]]"&gt;
                &lt;slide v-for="blog in blogs.blogs" :key="blog.id" v-if="currentBlogDate &gt;= blog.created &amp;&amp; blog.created"&gt;
                  &lt;b-card class="text-center m-3 p-0 p-md-3"&gt;
                    &lt;h4 class="display-4 font-weight-normal mb-3"&gt;{{ blog.title | striphtml | truncate(32, '...') }}&lt;/h4&gt;
                    &lt;b-card-text class="text-muted"&gt;{{ blog.body | striphtml | truncate(32, '...') }}&lt;/b-card-text&gt;
                    &lt;b-button :to="'/posts/view/' + blog.title" size="sm" variant="primary"&gt;Read More&lt;i class="fas fa-angle-right pl-2"&gt;&lt;/i&gt;&lt;/b-button&gt;
                  &lt;/b-card&gt;
                &lt;/slide&gt;
              &lt;/carousel&gt;
  </code></pre>
  
  <p>The error:</p>
  
  <pre><code>TypeError: Cannot read property 'indexOf' of undefined
  </code></pre>