[Vuejs]-"export 'default' " <imported as '__vue_script__'> was not found in '!!babel-loader

Try exporting your component in Footer.vue like:

<script>
  import "./assets/js/core.min.js";

  export default {
    name: 'Footer'
  }
</script>

If you have some minutes you might want to read https://frontendsociety.com/why-you-shouldnt-use-vue-component-ff019fbcac2e.