What is the problem webstorm shows all the code in errors and warnings, but the code works and is correct?

Question

JavaScript

I open the js file and everything is in errors, I didn’t change anything, I didn’t redo it in the code, but I could have hurt something in the WebStorm settings, but I can’t understand or remember what, I didn’t do anything special there either. Can I somehow reset the analyzer or something like that? Apart from reinstalling of course.
Everything was fine before.

Answer 1

JS is like that. It may be incorrect in places. But it still works.
The browser digests a lot.
We are not telepaths - specific examples are needed.

Answer 2

Eslint can be included or the config got to the project?