.eslintrc.js

module.exports = {
  parserOptions: {
    ecmaVersion: 7,
    sourceType: 'module',
    ecmaFeatures: {
      impliedStrict: true,
      experimentalObjectRestSpread: true
    }
  },
  parser: 'babel-eslint',
  plugins: ['flowtype'],
  env: {
    es6: true,
    node: true
  },
  rules: {
    'no-unused-vars': [
      'error',
      {
        vars: 'all',
        args: 'after-used'
      }
    ],
    'linebreak-style': [2, 'unix'],
    'eol-last': 2,
    'no-var': 2,
    'prefer-const': 2,
    'no-multiple-empty-lines': [
      2,
      {
        max: 2
      }
    ],
    'no-console': 0,
    'no-extra-bind': 2,
    'no-undef': 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/use-flow-type': 1,
    'flowtype/valid-syntax': 1
  }
};