Xo: Integrate the `prettier` module

[hugomrdias]

would you consider using or doing something like https://github.com/kentcdodds/prettier-eslint for xo --fix ?

more links
https://github.com/jlongster/prettier
https://github.com/kentcdodds/prettier-eslint-cli

[sindresorhus]

Maybe. I'm gonna give it some time to mature first. Right now it's very buggy. I'll keep this issue open.

[lydell]

Relevant: https://github.com/not-an-aardvark/eslint-plugin-prettier

(I use it and think it's great.)

[lndgalante]

@sindresorhus we will see this feature in a near future ? thanks!

[jangerhofer]

Heads-up: Prettier has just hit v1.0!

I found this issue because I do not fully understand what differentiates Prettier from XO. Wouldn't a Prettier plugin duplicate XO's functionality?

[lndgalante]

@jangerhofer Prettier is a formatter and XO is a linter that uses ESLint underneath

[fregante]

Oh no. Every time I try prettier I don't like its tricks to shorten the lines.

Before prettier

After prettier

Why.

[lipis]

Prettier is really mature now and can be easily integrated.. here is an example on how to use it with ESLint https://github.com/lipis/prettier-setup

[pvdlg]

Prettier is really stable for a while now and used in many large projects (in particular most of Facebook code).

It can be integrated with xo or eslint pretty easily with eslint-plugin-prettier and eslint-config-prettier:

• eslint-config-prettier disable all the eslint formatting rules (rules related to comma, spaces etc but not the rules related to code issues) that are covered by prettier.
• eslint-plugin-prettier report errors/warnings when some code is formatted differently than the prettier format and allow to automatically fix it with --fix.

In order to use it with xo it can be configured this way in package.json:

"devDependencies": {
  "eslint-config-prettier": "^2.8.0",
  "eslint-plugin-prettier": "^2.3.0",
  "prettier": "^1.8.2",
  "xo": "^0.18.2"
},
"prettier": {
  // Any other prettier options
  "singleQuote": true
},
"xo": {
  "extends": [
    "prettier"
  ],
  "plugins": [
    "prettier"
  ],
  "rules": {
    "prettier/prettier": "error"
  }
}

It works well but it requires some configuration and devDpendencies.

In xo we could:

• Add a prettier option (true or false, false by default)
• if prettier option is true add eslint-plugin-prettier and eslint-config-prettier and the rule "prettier/prettier": "error"

Would you be open to such PR?