eslint --init does not work with @flow

Tell us about your environment macOS Sierra 10.12.1

• ESLint Version: v3.3.1
• Node Version: v6.9.1
• npm Version: v3.10.8 What parser (default, Babel-ESLint, etc.) are you using? babel-eslint Please show your full configuration:

{
  "devDependencies": {
    "babel-cli": "^6.18.0",
    "babel-eslint": "^7.1.0",
    "babel-jest": "^17.0.0",
    "babel-plugin-transform-flow-strip-types": "^6.18.0",
    "babel-preset-es2015": "^6.18.0",
    "eslint": "^3.9.1",
    "eslint-config-airbnb": "^13.0.0",
    "eslint-plugin-flowtype": "^2.25.0",
    "eslint-plugin-import": "^2.2.0",
    "eslint-plugin-jsx-a11y": "^3.0.1",
    "eslint-plugin-react": "^6.6.0",
    "flow-bin": "^0.34.0",
    "jest": "^17.0.0"
  }

What did you do? Please include the actual source code causing the issue.

./node_modules/.bin/eslint --init

What did you expect to happen? I have a project with flow annotations that I wanted to use as a source for my custom .eslintrc file and it breaks.

I guess we have two options:

1. Either we strip the annotations when it is a flow annotated file and then run eslint --init…
2. Or we support natively from eslint itself flow annotations (maybe taking them from eslint-plugin-flowtype?)

Whatever is chosen I would be happy to help and implement the solution! 😄

What actually happened? Please include the actual, raw output from ESLint.

Determining Config: 0% [------------------------------] 0.0s elapsed, eta 0.0s 

(/Users/flaviocorpa/WebstormProjects/flow-linq/src/List.js:16:11) Parsing error: Unexpected token <
Error: (/Users/flaviocorpa/WebstormProjects/flow-linq/src/List.js:16:11) Parsing error: Unexpected token <
    at getSourceCodeOfFile (/Users/flaviocorpa/WebstormProjects/flow-linq/node_modules/eslint/lib/util/source-code-util.js:39:15)
    at /Users/flaviocorpa/WebstormProjects/flow-linq/node_modules/eslint/lib/util/source-code-util.js:95:28
    at Array.forEach (native)
    at getSourceCodeOfFiles (/Users/flaviocorpa/WebstormProjects/flow-linq/node_modules/eslint/lib/util/source-code-util.js:94:15)
    at configureRules (/Users/flaviocorpa/WebstormProjects/flow-linq/node_modules/eslint/lib/config/config-initializer.js:131:23)
    at processAnswers (/Users/flaviocorpa/WebstormProjects/flow-linq/node_modules/eslint/lib/config/config-initializer.js:254:18)
    at .completed (/Users/flaviocorpa/WebstormProjects/flow-linq/node_modules/eslint/lib/config/config-initializer.js:414:30)
    at PromptUI.onCompletion (/Users/flaviocorpa/WebstormProjects/flow-linq/node_modules/inquirer/lib/ui/prompt.js:57:10)
    at AnonymousObserver.Rx.AnonymousObserver.AnonymousObserver.completed (/Users/flaviocorpa/WebstormProjects/flow-linq/node_modules/rx-lite/rx.lite.js:1550:12)
    at AnonymousObserver.Rx.internals.AbstractObserver.AbstractObserver.onCompleted (/Users/flaviocorpa/WebstormProjects/flow-linq/node_modules/rx-lite/rx.lite.js:1489:14)

I had a look at the code and it breaks when reading the first generic:

class List<T> {
          ^^^

Thanks in advance!

[nzakas]

I don’t think we should make a change here. There’s no guarantee that core rules work correctly with Flow, TypeScript, or any other dialect other than plain JS. I’m not sure there’s much value to most users in going through the process if we can’t know whether or not the results will be useful.

[platinumazure]

I’ve reproduced this, so I’m labeling this as a bug for now.

It might be that other parsers or experimental features are “not supported”, in which case this might turn into an enhancement request. Either way, I think we can improve the experience here.

Thanks for the report!