.eslintrc.js

const branch = require('child_process').execSync('git rev-parse --abbrev-ref HEAD').toString().trim()
const warnOrError = branch === 'master' ? 'error' : 'warn'

module.exports = {
  parser: 'babel-eslint',
  env: {
    browser: true,
    es6: true,
    node: true
  },
  extends: ['eslint:recommended', 'plugin:react/recommended'],
  parserOptions: {
    ecmaVersion: 7,
    ecmaFeatures: {
      experimentalObjectRestSpread: true,
      jsx: true
    },
    sourceType: 'module'
  },
  plugins: ['react'],
  rules: {
    indent: [
      warnOrError,
      2,
            { SwitchCase: 1 }
    ],
    'linebreak-style': [
      warnOrError,
      'unix'
    ],
    semi: [
      warnOrError,
      'never'
    ],
    'no-warning-comments': ['off'],
    'comma-dangle': ['off'],
    'brace-style': [warnOrError, '1tbs', { allowSingleLine: true }],
    quotes: [warnOrError, 'single', { avoidEscape: true }],
    'quote-props': [warnOrError, 'as-needed'],
    'no-console': ['off'],
    'no-unused-vars': [warnOrError],
    'no-var': [warnOrError],
    'no-empty': [warnOrError],
    'no-multi-spaces': [warnOrError],
    'no-trailing-spaces': [warnOrError],
    'space-before-blocks': [warnOrError],
    'padded-blocks': [warnOrError, 'never'],
    'key-spacing': [warnOrError],
    'arrow-spacing': [warnOrError],
    'keyword-spacing': [warnOrError],
    'space-infix-ops': [warnOrError, { int32Hint: false }],
    'space-before-function-paren': [warnOrError, {
      anonymous: 'always',
      named: 'never',
      asyncArrow: 'always'
    }],
    'new-parens': [warnOrError],
    'react/no-danger': [warnOrError],
    'react/prop-types': [warnOrError],
    'react/no-direct-mutation-state': [warnOrError],
    'react/jsx-indent': [warnOrError, 2],
    'react/jsx-curly-spacing': [warnOrError, 'never'],
    'react/jsx-closing-bracket-location': [warnOrError, {
      nonEmpty: 'after-props',
      selfClosing: 'after-props'
    }],
    'react/jsx-space-before-closing': [warnOrError, 'always'],
    'react/jsx-max-props-per-line': [warnOrError, { maximum: 1 }],
    'react/jsx-indent-props': [warnOrError, 2],
    'react/jsx-first-prop-new-line': [warnOrError, 'multiline'],
    'object-curly-spacing': [warnOrError, 'always'],
    'comma-spacing': [warnOrError, {
      before: false,
      after: true
    }],
    'array-bracket-spacing': [warnOrError, 'never'],
    'computed-property-spacing': [warnOrError, 'never'],
    'space-in-parens': [warnOrError, 'never']
  }
}