feature request: prefer ["_"] over lsp fallback

[blyedev]

Did you check existing requests?

• I have searched the existing issues

Describe the feature

Prefer ["_"] filetype over lsp format.

Provide background

I want to configure prettier so it's the default formatter for everything unless a different formatter was configured. If prettier does not format a file I would like the lsp to.

Currently the lsp is preffered over the ["_"] filetype which i would consider to be counterintuitive.

What is the significance of this feature?

nice to have

Additional details

Obviously I could just configure prettier for every file but that feels pretty annoying and verbose for the config

[stevearc]

If prettier does not format a file I would like the lsp to.

I assume that by this you mean that you want to attempt to run prettier and, if it does not format the file, fall back to LSP. Conform doesn't do this kind of logic because it would require parsing errors from the formatters to determine if they failed because the file isn't supported or for some other reason. Better to just let the user configure the formatters they want for the filetypes they want.

If the current syntax doesn't support exactly what you need, I recommend writing your own function to define what formatters to use. You can do that on a per-filetype basis like we do in this example, or you can do it for all filetypes by defining a custom format-on-save function like we do here. In any case, you have to decide which formatters to use ahead of time. The fallback behavior is only for situations where a formatter is not installed, or the LSP is not available, or a formatter has a condition that returns false.

[blyedev]

I now realize I forgot to add the context as to why I was using ["_"] mistakenly assuming it self-explanatory.

I wanted prettier to run only if nothing else was configured and only then fall back to the lsp if prettier fails.

Nonetheless the suggestion you provided answers my question either way. Thank you for your support!