.eslintrc

{
  "parser": "babel-eslint",
  "plugins": ["babel", "react", "flowtype"],
  "parserOptions": {
    "ecmaVersion": 2017,
    "sourceType": "module",
    "ecmaFeatures": {
      "jsx": true,
      "modules": true,
      "blockBindings": true,
      "defaultParams": true,
      "forOf": true,
      "generators": true,
      "objectLiteralComputedProperties": true,
      "objectLiteralDuplicateProperties": false,
      "objectLiteralShorthandMethods": true,
      "objectLiteralShorthandProperties": true,
      "templateStrings": true,
      "experimentalObjectRestSpread": true
    }
  },
  "rules": {
    "quotes": [2, "single"],
    "strict": [2, "never"],
    "semi": [2, "never"],
    "brace-style": [2, "1tbs", {
      "allowSingleLine": true
    }],
    "comma-style": ["error", "first"],
    "comma-dangle": [2, "never"],
    "no-dupe-keys": 2,
    "no-ex-assign": 2,
    "no-extra-semi": 2,
    "valid-typeof": 2,
    "no-template-curly-in-string": "error",
    "symbol-description": "error",
    "prefer-arrow-callback": ["error", {"allowNamedFunctions": true}],

    "babel/generator-star-spacing": 1,
    "babel/object-shorthand": 1,
    "babel/arrow-parens": 1,
    "babel/no-await-in-loop": 1,
    "babel/flow-object-type": [ "error", "comma" ],
    "babel/func-params-comma-dangle": 1,

    "react/jsx-uses-react": 2,
    "react/jsx-uses-vars": 2,
    "react/react-in-jsx-scope": 2,

    "flowtype/define-flow-type": 1,
    "flowtype/require-parameter-type": 1,
    "flowtype/require-return-type": [
      1,
      "always",
      {
        "annotateUndefined": "never"
      }
    ],
    "flowtype/space-after-type-colon": [
      1,
      "always"
    ],
    "flowtype/space-before-type-colon": [
      1,
      "never"
    ],
    "flowtype/type-id-match": [
      1,
      "^([A-Z]{1,3}[a-z0-9]+)+Type$"
    ],
    "flowtype/use-flow-type": 1,
    "flowtype/valid-syntax": 1
  },
  "settings": {
    "flowtype": {
      "onlyFilesWithFlowAnnotation": true
    }
  },
  "env": {
    "es6": true,
    "browser": true,
    "node": true
  }
}