eslint_local formatter and eslint-plugin-node shebang issue

[gautaz]

Hello,

Currently autoformat needs to use a temporary file when using eslint to avoid modifying the project filesytem and still being able to get the fixed content back in the current buffer.
When using the eslint-plugin-node eslint plugin with the shebang rule, it ends up with autoformat removing the shebang line from files where it should be kept.
This is because eslint operates on a temporary file which obviously has not the same path as the original file present on the project's filesystem, thus the shebang rule from the eslint-plugin-node eslint plugin cannot assert the right fix.

I am trying to find a way to work this around and the only solution that comes to mind for the moment would be:

1. Copying the file to lint to a temporary file
2. Operating eslint on the original file and reflecting the modifications in the vim buffer
3. Copying back the temporary file to the original file

I have no idea if this might work, any advice is welcome.
Would you accept a PR for this? (I am not fluent in vimscript but I can try)

Thanks for autoformat anyway :-).

[chtenb]

If you look at the current code for eslint integration you can see it's already horrific. Imagine what any additional magic will do to it :)

I think it would be a lot wiser to patch ESLint to be able to print the results to stdout, like all other sane formatters do.

[gautaz]

@Chiel92 Agreed, I'll look into it, is there an already opened issue on eslint related to that?

[chtenb]

I'm not sure, there could be

[gautaz]

Looking deeper in eslint documentation and what have been done for ALE, it seems that the favored solution provided by eslint for this need is to use --stdin --fix-dry-run --format=json in combination with --stdin-filename.

@Chiel92 Does this seem more acceptable?
It avoids completely the need for a temporary file but adds some boilerplate to parse the JSON output...

[chtenb]

That sounds acceptable