.eslintrc

{
  "plugins": [
    "react"
  ],
  "parserOptions": {
    "ecmaVersion": 6,
    "sourceType": "module",
    "ecmaFeatures": {
      "jsx": true
    }
  },
  "env": {
    "es6":     true,
    "browser": true,
    "node":    true,
    "mocha":   true
  },
  "extends": [
    "eslint:recommended",
    "plugin:react/recommended"
  ],
  "rules": {
    // first argument: 0 - silent, 1 - warning, 2 - error
    "strict": [ 2, "safe" ],
    "no-debugger": 2,
    "brace-style": [
      2,
      "1tbs",
      { "allowSingleLine": true }
    ],
    "no-trailing-spaces": 2,
    "keyword-spacing":    2,
    "space-before-function-paren": [
      2,
      "never"
    ],
    "spaced-comment":     [2, "always" ],
    "vars-on-top":        2,
    "no-undef":           2,
    "no-undefined":       2,
    "comma-dangle":       [ 0, "never" ],
    "quotes":             [ 2, "single" ],
    "semi":               [ 2, "always" ],
    "guard-for-in":       2,
    "no-eval":            2,
    "no-with":            2,
    "valid-typeof":       2,
    "no-unused-vars":     2,
    "no-continue":        1,
    "no-extra-semi":      1,
    "no-unreachable":     1,
    "no-unused-expressions": 1,
    "no-magic-numbers":   1,
    "max-len":            [1, 120, 4],
    "react/prefer-es6-class": 1
  }
}