Set "endOfLine" to auto in prettier config

[allejo]

Prettier by default uses LF but when working on a cross-platform repo where we let git handle the CRLF <> LF conversions for us. This default behavior causes Prettier and Git to start battling with each other and causes lint checks to fail. By setting it to auto, Prettier will respect the line endings that exist on the file and not change them.

[b-kelly]

I'm not sure if I want to set this in the Prettier config or not. For reference, when running checks in GH actions / via package.json, we set that value explicitly. See Stacks-Editor as an example:

{
  "scripts": {
    "lint:prettier": "prettier --check . --end-of-line auto",
  }
}

[allejo]

If you set --end-of-line in the command line, would that take precedent over the loaded configuration file? If so, then wouldn't that allow users to opt-in to some line ending behavior whenever it's run? Git will always be the last operation (e.g. you make a commit) to handle CRLF <> LF conversions.

[b-kelly]

Prettier will set any command line options over existing config settings (which are in turn set over any default setting). What the given command does is force prettier to use endOfLine: auto whenever someone runs npm run lint:prettier. This all happens only during the command's execution, so you can generally ignore any other environmental factors (such as what git or your OS has decided what your line endings should be). Something to note is that as-written, prettier is only checking, not modifying.

[allejo]

Right, the script above is only checking and not modifying any files. I haven't tried yet, but do IDEs support pulling in a configuration from a package? Like, what if your IDE is configured to do a "prettier on save" function, would it modify the line ends to LF and then cause Git to see that as the file being changed?

[giamir]

@b-kelly I believe we could consider endOfLine: "auto" a sensible default for our Stack Overflow repositories which would make it a good candidate for this package. What about merging this PR and cut a release?