Nudge forward style checks a la eslint-config-standard

[paulmelnikow]

Because I despise nitpicking stuff like indentation and spacing in pull request comments, I'd like to nudge forward our automated style checking, at least for new files being added.

I don't want to totally rewrite server.js just to get automated style checking… the blame tracking is just too useful. So let's it's just take care of that when we start splitting it out.

More discussion in #948.

[Daniel15]

Before committing this, consider using Prettier instead. Maybe we could enable Prettier on all files except server.js?

[paulmelnikow]

I'd support dropping it in for the files except server.js. Here's what I wrote about Prettier in #948:

I'm open to pursuing Prettier at some point in the future. It seems a much better solution for formatting. However it doesn't handle the semantic issues, so it doesn't keep us from also needing an eslint config.

[Daniel15]

Thanks @paulmelnikow, I missed that comment

However it doesn't handle the semantic issues, so it doesn't keep us from also needing an eslint config.

That's true. However, using a combination of ESLint + Prettier works well. I think you can even run Prettier via ESLint (that is, there's a custom ESLint rule that runs Prettier).

[paulmelnikow]

However, using a combination of ESLint + Prettier works well.

I'm definitely down for that! Let's do it.

[Daniel15]

I think this is the ESLint plugin I was thinking of: https://github.com/prettier/eslint-plugin-prettier. It supports only running prettier on files that have a particular docblock tag in them (eg. @prettier), which we could add to all files except server.js. This is similar to what we do internally at Facebook (except we have some custom integration rather than using this particular ESLint plugin).

There's also eslint-config-prettier that disables ESLint rules that conflict with Prettier. This lets you use some shared ESLint config along with Prettier and not experience any conflicts.