Have --check output be in different formats (pretty/unified/json)

[levouh]

In summary, add an argument to dump the formatted file to STDOUT rather than doing things in-place, say, --stdout/-d mode.

An alternative that I've used with a number of different tools is to pass diff output to patch in order to reconstruct what the changed file would look like. For stylua, something like stylua --check /path/to/file.lua | patch -p0 -s -o -. However, the --check option does not output a patch-able format (to my knowledge) so doing something like this doesn't give the "final" output either.

Given the former option of adding a new argument or similar, discerning which STDOUT applies to which file can be difficult as well, so it seems absolutely viable to have stylua only accept a single file when being run in either of these modes.

Thoughts @JohnnyMorganz?

[JohnnyMorganz]

You can pass code into stdin, then its formatted output is dumped to stdout (cat /path/to/file.lua | stylua -). Is this reasonable for your use case, or is it necessary that we take in a path instead?

For --check outputing a patch-able diff, that might be nice to have. I assume patch takes in a git-style diff? If we do this, it also might help editor integrations aswell, where they can patch parts of the file rather than currently replacing the whole file buffer with the formatted output, losing some niceties.

[levouh]

You can pass code into stdin, then its formatted output is dumped to stdout (cat /path/to/file.lua | stylua -). Is this reasonable for your use case,

Awesome, this satisfies 99% of my use case, but it still seems like it'd be worth it to have an option to explicitly pass the output to STDOUT.

or is it necessary that we take in a path instead?

Its effectively the same thing; I know the path so I'm either just outputting the file or passing it to stylua directly.

I assume patch takes in a git-style diff?

Yes, exactly. I'm not familiar with it enough to decoratively say whether or not:

it also might help editor integrations aswell, where they can patch parts of the file

is something that is easily done, but I cannot imagine it hurts either way. Depends on how easy it is to do and the complexity that it adds to stylua itself. If it's easy, etc. then it might be worth it, but if you have the start/end state of the file, it isn't too hard to form a git-style diff via some light scripting (implying it is something users can easily add themselves at no cost to the complexity of this project.

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So TLDR, either of the things you mentioned would be nice, but given it is possible to dump a file to STDOUT like you mentioned, that is completely fine for my use case (although perhaps you should document it somewhere [unless I just missed it while skimming]).

Feel free to close this if you want, or leave it open to track any changes you see fit.

[JohnnyMorganz]

I think I'll leave the formatting dumped to stdout when taking in a path for now, since it can be done externally with cat and piping.

Having --check output in a more patch-friendly/machine-friendly format seems like a reasonable addition though. Probably through something like --output pretty/unified/json where pretty is current, unified is patch-able, json is the diff output in json. Will probably add something like that when I have some time.

[JohnnyMorganz]

This is now supported in v0.13.0: https://github.com/JohnnyMorganz/StyLua/releases/tag/v0.13.0