Code Quality: code formatting & linting

[ptrxyz]

I find that eslint seems to be setup as a linter and code formatter for .js-type files. However it seems there is no linting/code formatting set up for (S)CSS. For that reason, I suggest to enable one.

While there is a wide variety on code formatters and linters for CSS, I would suggest to establish a consistent tool chain for linting and code formatting:

Linters for code quality checking only:

• eslint for JS-like objects
• stylelint for CSS-like objectes
• Prettier as a code formatter for both, JS and CSS likes (and of course HTML, Markdown, or whatever else is needed), as it is supported by (nearly) all code editors and integrates the above mentioned linters painlessly

Further, I would advocate to include a .editorconfig file in the git repo to make modern editors "agree" on a common formatting style while editing.

Note: While Ruby seems a bit out of competition here, one could also use the same concept of separating formatting and linting functionality to have a more consistent tool chain for Ruby files too: prettier apply rubocop's formatting settings and replace rubocop as a formatter, leaving it in place as a linter.

[NRayya]

Recommendation: Do the linting on the local level, CI should only throw warnings and block the merging.