bug#47488: Treatment of # in js.el

[Dmitry Gutov]

On 11.05.2021 15:21, Lars Ingebrigtsen wrote:
> Dmitry Gutov <dgutov@yandex.ru> writes:
>
> > We could add a custom var that disables this behavior, of
> > course. js2-mode has one, but it only affects the parser, not the
> > indentation behavior.
>
> If we could avoid having a user option, that's be nice...

Probably not without seeing an occasional false positive, e.g. ...

> > Maybe check against a specific list of preprocessor instructions, such
> > as #define, #ifdef, etc.
>
> I think that sounds like a good solution.  Grepping around a bit,
> perhaps `cpp-font-lock-keywords-source-directives' in font-lock.el would
> be a good source to use here?

... looking at the regexp it also matches #file, #line or #warning.

Each of these could also be a name of a private attribute, I think. 
Still, if those are indeed standard preprocessor directives, this var 
looks like a good choice.