.eslintrc.json

{
  "extends": [
    "airbnb-base",
    "prettier"
  ],
  "plugins": [
    "prettier"
  ],
  "root": true,
  "env": {
    "browser": true,
    "es6": true
  },
  "parser": "babel-eslint",
  "globals": {
    "Drupal": true,
    "drupalSettings": true,
    "drupalTranslations": true,
    "domready": true,
    "jQuery": true,
    "_": true,
    "matchMedia": true,
    "Backbone": true,
    "Modernizr": true,
    "Popper": true,
    "Sortable": true,
    "CKEDITOR": true
  },
  "rules": {
    "prettier/prettier": "error",
    "consistent-return": [
      "off"
    ],
    "no-underscore-dangle": [
      "off"
    ],
    "max-nested-callbacks": [
      "warn",
      3
    ],
    "import/no-mutable-exports": [
      "warn"
    ],
    "no-plusplus": [
      "warn",
      {
        "allowForLoopAfterthoughts": true
      }
    ],
    "no-param-reassign": [
      "off"
    ],
    "no-prototype-builtins": [
      "off"
    ],
    "valid-jsdoc": [
      "warn",
      {
        "prefer": {
          "returns": "return",
          "property": "prop"
        },
        "requireReturn": false
      }
    ],
    "no-unused-vars": [
      "warn"
    ],
    "operator-linebreak": [
      "error",
      "after",
      {
        "overrides": {
          "?": "ignore",
          ":": "ignore"
        }
      }
    ],
    "arrow-body-style": [
      "error",
      "always"
    ],
    "no-restricted-properties": [
      2,
      {
        "object": "Math",
        "property": "disallowedPropertyName"
      }
    ]
  }
}