If you're writing typescript Vue code, tsc will complain when you do import Doc from 'Doc.md'. You need to add a shim (ambient typescript module declaration) to tell tsc that a .md is a Vue component:

% cat src/shims-md.d.ts
declare module '*.md' {
  import Vue from 'vue'
  export default Vue
}

Otherwise when building, you will get errors about missing components.