.eslintrc.json

{
  "extends": "google",

  "parserOptions": {
    "ecmaVersion": 2017,
    "sourceType": "module",
    "ecmaFeatures": {
      "experimentalObjectRestSpread": true
    }
  },

  "plugins": ["async-await"],

  "env": {
    "es6": true
  },

  "globals": {
    "window": true,
    "document": true,
    "it": true,
    "expect": true,
    "Event": true,
    "CustomEvent": true
  },

  "rules": {
    "no-multiple-empty-lines": ["error", {
      "max": 1,
      "maxEOF": 0,
      "maxBOF": 0
    }],

    "no-unused-vars": "off",
    "no-warning-comments": "off",
    "no-cond-assign": "error",
    "no-extra-parens": "error",
    "no-extra-semi": "error",
    "no-irregular-whitespace": "error",
    "no-unreachable": "error",
    "valid-typeof": "error",

    "block-scoped-var": "error",
    "consistent-return": "error",
    "curly": ["error", "all"],
    "brace-style": ["error", "1tbs"],
    "default-case": "error",
    "dot-notation": "error",
    "eqeqeq": "error",
    "radix": "error",
    "comma-spacing": ["error", {"before": false, "after": true}],
    "space-infix-ops": "error",
    "space-before-function-paren": ["error", "always"],
    "quotes": ["error", "single", {"avoidEscape": true}],
    "comma-dangle": ["error", "always-multiline"],
    "no-useless-constructor": "off",
    "no-debugger": "off",
    "require-jsdoc": "off",
    "guard-for-in": "off",
    "no-extend-native": "off",
    "prefer-rest-params": "off"
  }
}