@suricactus you need to read about the language protocol this is because your using type script as linter
Duplicate of https://github.com/microsoft/TypeScript/pull/30829
This is definitely not a duplicate of the typescript bug in #30829
It would be best to not confuse type script issues and javascript issues.

The TypeScript project powers vs code鈥檚 JavaScript intellisense
update on the PR to add ES private class fields to TS: https://github.com/microsoft/TypeScript/pull/30829#issuecomment-563337384
Most helpful comment
The TypeScript project powers vs code鈥檚 JavaScript intellisense