I'm quite new to Nuxtjs so I made a test project which purpose is merely the (of course) testing of Nuxtjs functionalities.

Currently I'm trying to create a simple custom module: afaik a module is basically a wrapper around a vou/js library/plugin, something like a high-level integration used to expose configurations on how the underlying library/plugin is imported and used in the Nuxt application.

So I'm trying with a simple module that declare some plain js classes that I'll use in my application, e.g. Order and Product, and that's what I came out with:

Directory structure

pages
  the-page.vue
modules
  classes
    index.js
    order.js

/modules/classes/index.js

const path = require('path')

export default function (moduleOptions) {
    const { nuxt } = this

    // add the debug plugin
    this.addPlugin({
        src: path.resolve(__dirname, 'order.js'),
    })
}

/modules/classes/order.js

class Order {
    constructor(id) {
        this.id = id;

        console.log('created order #' + this.id);
    }
}

export {Order};

/nuxt.config.js

export default {
  // ...
  buildModules: [
    // ...
    '~/modules/classes'
  ],
  // ...
}

/pages/the-page.vue

<script>
export default {
  name: 'ThePage',
  data () {
    return {
    }
  },
  methods: {
    createOrder () {
      const order = new Order(123)
    }
  }
}
</script>

The error

My defined class are still not imported in my pages:

/app/pages/the-page.vue
  18:13  error  'order' is assigned a value but never used  no-unused-vars
  18:25  error  'Order' is not defined                      no-undef

Considerations

Probably I'm missing something about modules usage and/or implementation, but every tutorial I found starts with too complex scenarios, and since I'm at the beginning with Nuxtjs I need something easier to implement.