Add "target_files" option to config file

[nwshane]

Current behavior:

No option (as far as I can tell) to specify the glob I want to target in the .prettierrc config file.

Expected behavior:

It would be great to have a "target_files" option in the .prettierrc config file, which would allow you to specify which files you want prettier to target. That way, I could configure my editor's prettier linter only to change files that match the glob. Right now, there seems to be a .prettierignore file which my editor's linter can use, but .prettierignore only allows blacklisting files instead of whitelisting files.

I hope this request makes sense! I love prettier - thanks for all your awesome work.

[ikatyang]

Similar to #3460 but in config file.

If we're going to add this feature, I'd expect --config should be provided explicitly since it's a project-level config and the default behavior is to find config files up to the tree for each file, which is impossible to get the correct glob.

[azz]

(Kind of) duplicate of #2691. I think it could be confusing having file lists in the config file. Instead we should default the CLI to run on **/{js,ts,css,...} (#3503).

[ikatyang]

How about adding an enable: boolean option so that we could select/ignore files using overrides? though there's already a requirePragma.

[hawkrives]

Oh that's a good idea. Ignore certain patterns by setting requirePragma. I'll have to steal that.

[ikatyang]

After second thought, I think using requirePragma should be enough since nobody will use requirePragma and want to ignore files contains pragma, and it should be supported by every editor integration. (And it does not need to set --config explicitly if we want to add this feature.)

prettier "**/*.{js,ts,css}" --write 

{
  "requirePragma": true,
  "overrides": [
    {
      "files": ["glob-you-want-to-format"],
      "excludeFiles": ["glob-you-want-to-ignore"],
      "options": { "requirePragma": false }
    }
  ]
}

Feel free to reopen if it does not address the issue.

[nwshane]

@ikatyang Thanks a lot! This solves most of my issue, although there's still one improvement I'd love to be able to make. At the moment, I have my file glob (frontend/src/**/*.{css,js,json,less}) defined twice: once in an npm script that uses the prettier command, and again in the prettier config file. Ideally I'd like to be able to define it only once, presumably in the configuration file, and let the prettier CLI command just use the config file's settings by default. That way, I won't have to remember to always change the glob in two places in the future.

The prettier command currently errors out if it's not provided with a glob. Would you consider changing prettier so that it doesn't require a glob, in order to make the config file the "source of all truth"?

[azz]

@nwshane We have, and will probably do this in Prettier 2.0 (#3503)

#2691 - CLI defaults to "**/*.{js,ts,...}".
People should just be able to do prettier --write without passing messy globs #0CJS