chore: add linting with Prettier

[vickyyyyyyy]

Currently, we do not have linting in the project.

Work done:

• Added .prettierrc.js config file to look at @grafana/toolkit's linting rules (see more at https://www.npmjs.com/package/@grafana/toolkit)
• Ran it to fix current linting issues.

Questions:

• Do we only care about linting tsx | ts | js files? I have it looking at everything here at the moment
• Should we use Prettier as it is also used in @grafana/toolkit (as is done in this PR at the moment) or should we use eslint because it is used in grafana-ui? https://github.com/grafana/grafana/blob/1d2b839a1dc197cce755d76e6ffc872e8ae4c8c2/contribute/style-guides/frontend.md#linting. I tried both and they seem to have slightly different linting rules, would be good to get a consensus on this.

Example differences of Prettier vs eslint:

[stevenvachon]

Our standard eslint config has a prettier plugin, so I think that should be enough. Plugins have prettier configs as custom overrides and maybe also for auto-fixing code style and not full-on auto-lint. Prettier will reference an .editorconfig file, which unfortunately does not yet support extending/importing.

[vickyyyyyyy]

Our standard eslint config has a prettier plugin, so I think that should be enough. Plugins have prettier configs as custom overrides and maybe also for auto-fixing code style and not full-on auto-lint. Prettier will reference an .editorconfig file, which unfortunately does not yet support extending/importing.

I'm a bit confused by our standard eslint config - it looks like when we use that, it will replace single quotes to double quotes but it looks like we are using single quotes everywhere? How does that work?

[stevenvachon]

I don't see anything regarding quotes in https://github.com/grafana/eslint-config-grafana/blob/master/index.js unless it's coming from"plugin:prettier/recommended", which will get overridden by an .editorconfig file.

[vickyyyyyyy]

closing for now, looks like @kminehart found we are ignoring a prettier config generated by yarn build