Different JSDoc Intellisense Behaviour on Script Block and on JavaScript File

[jefrydco]

• I have searched through existing issues
• I have read through docs
• I have read FAQ

Info

• Platform: MacOS
• Vetur version: 0.26.1
• VS Code version: 1.48.1

Problem

This is intellisense in JavaScript file:

It shows description and example.

And this is intellisense in <script> block on Vue SFC:

It doesn't show description and example.

This is also occurrs on <script lang="ts"> block on Vue SFC:

Reproducible Case

• Create a index.js and export named function that has JSDoc description and example.
• Try to import it on JavaScript
• Try to import it on <script> block on Vue SFC

Minimal Reproduction: https://github.com/jefrydco/vue-intellisense-behaviour

[octref]

This is a special pre-processing recently added in VS Code: https://github.com/microsoft/vscode/blob/8ba70d8bdc3a10e3143cc4a131f333263bc48eef/extensions/typescript-language-features/src/utils/previewer.ts

I copied it over:

[octref]

While at it I fixed hover/completion as well: