better typescript support
similar to https://github.com/nuxt/nuxt.js/pull/2353 to js/jsx support
<!--cmty--><div align="right"><sub><em>This feature request is available on <a href="https://nuxtjs.cmty.io">Nuxt.js</a> community (<a href="https://nuxtjs.cmty.io/nuxt/nuxt.js/issues/c6950">#c6950</a>)</em></sub></div>