title: Vue I18n doesn't work on pure javascript files
body: <p>I implemented <a href="https://kazupon.github.io/vue-i18n/" rel="nofollow noreferrer">https://kazupon.github.io/vue-i18n/</a> i18n localization in my project. And it works very well on vue components/pages. But it doesn't work on pure javascript classes and mixins. Is there a way to handle it?</p>
  
  <p>In <strong>example.vue</strong> component:</p>
  
  <pre><code>&lt;template&gt;
  &lt;p&gt;{{ $t("message.hello") }}&lt;/p&gt;
  ...
  &lt;/template&gt;
  &lt;script&gt;
  data:(){
  ...
  },
  methods:...
  i18n: require('path of localization messages.')
  &lt;/script&gt;
  </code></pre>
  
  <p>But it is not work on <strong>example.js(pure javascript)</strong> or <strong>example.mjs(mixins)</strong> files.</p>