Vetur does not recognize extended types in js

[hidde-jan]

• [x] I have searched through existing issues
• [x] I have read through docs
• [x] I have read FAQ

Info

• Platform: macOs
• Vetur version: 0.24.0
• VS Code version: 1.45.1

Problem

Related to #1738, but it works for TypeScript, not for JS. Could be an issue with VSCode, but not certain.

When using Vetur and a plugin for Vue that extends the Vue constructor, Vetur does not recognize the new options when using JS, but does recognize them when using TypeScript. Of course, default options (name, props, etc.) are correctly typed in both JS and TS.

I've used the vue-socket.io-extended library as an example, same as in #1738:

JS:

TS:

Reproducible Case

Open each of the following repos with vscode, and check the HelloWorld component:

• https://github.com/hidde-jan/vetur-socket.io-extended-ts
• https://github.com/hidde-jan/vetur-socket.io-extended-js

[hidde-jan]

I also just noticed it doesn't autocomplete props:

If I reset the repository to the clean state (init commit done by vue create) it does work:

[jdz321]

I have the same issue.

[yoyo930021]

I think #1775.