title: How to use nuxt plugin in another file?
body: <p>I have 2 files in plugins folder</p>
  <p><code>helper.js</code> and <code>cryptojs.js</code></p>
  <p>in cryptojs.js</p>
  <pre><code>import Vue from 'vue'
  import VueCryptojs from 'vue-cryptojs'
  
  Vue.use(VueCryptojs)
  </code></pre>
  <p>in helper.js</p>
  <pre><code>import Vue from 'vue';
  
  const encrypt = (str) =&gt; {
     // how to use VueCryptojs plugin here ?
  }
  
  Vue.mixin({
      methods: {
         encrypt: encrypt 
      }
  }
  </code></pre>
  <p>How to use VueCryptojs plugin in helper file? thanks</p>