.eslintrc.json

{
  "root": true,
  "parserOptions": {
    "ecmaVersion": 2017,
    "ecmaFeatures": {
      "experimentalObjectRestSpread": false,
      "globalReturn": false,
      "impliedStrict": false,
      "jsx": false
    },
    "sourceType": "script"
  },

  "env": {
    "browser": true,
    "es6": true,
    "jquery": true,
    "node": false
  },

  "plugins": [],

  "globals": {
    "document": false,
    "navigator": false,
    "window": false,
    "Drupal": true
  },

  "extends": "eslint:recommended",

  "rules": {
    "for-direction": "error",
    "getter-return": "error",
    "no-await-in-loop": "error",
    "no-extra-parens": ["error", "all", {"nestedBinaryExpressions": false}],
    "no-prototype-builtins": "off",
    "no-template-curly-in-string": "error",

    "accessor-pairs": "error",
    "array-callback-return": "error",
    "block-scoped-var": "off",
    "curly": ["error", "all"],
    "dot-notation": "off",
    "guard-for-in": "error",
    "no-caller": "error",
    "no-empty-function": "error",
    "no-eq-null": "error",
    "no-eval": "error",
    "no-extend-native": "error",
    "no-extra-bind": "error",
    "no-extra-label": "error",
    "no-fallthrough": "error",
    "no-floating-decimal": "error",
    "no-implicit-coercion": "error",
    "no-implicit-globals": "error",
    "no-implied-eval": "error",
    "no-invalid-this": "off",
    "no-iterator": "error",
    "no-labels": "error",
    "no-lone-blocks": "error",
    "no-loop-func": "error",
    "no-multi-spaces": "error",
    "no-multi-str": "error",
    "no-new": "error",
    "no-new-func": "error",
    "no-new-wrappers": "error",
    "no-octal-escape": "error",
    "no-param-reassign": "off",
    "no-proto": "error",
    "no-redeclare": "off",
    "no-return-assign": "error",
    "no-return-await": "error",
    "no-script-url": "error",
    "no-self-assign": "error",
    "no-self-compare": "error",
    "no-sequences": "error",
    "no-throw-literal": "off",
    "no-unmodified-loop-condition": "error",
    "no-unused-expressions": "error",
    "no-unused-labels": "error",
    "no-useless-call": "error",
    "no-useless-concat": "error",
    "no-useless-return": "error",
    "no-void": "error",
    "no-warning-comments": ["error", {"terms": ["debug", "fixme", "xxx"], "location": "start"}],
    "no-with": "error",
    "radix": ["error", "always"],
    "require-await": "error",
    "vars-on-top": "off",
    "wrap-iife": ["error", "inside"],

    "strict": ["error", "function"],

    "init-declarations": "off",
    "no-shadow-restricted-names": "error",
    "no-undef-init": "error",
    "no-undefined": "error",
    "no-unused-vars": ["error", {"args": "none"}],
    "no-use-before-define": "off",

    "array-bracket-newline": ["error", "consistent"],
    "array-bracket-spacing": ["error", "never"],
    "array-element-newline": "off",
    "block-spacing": ["error", "always"],
    "brace-style": ["error", "stroustrup"],
    "camelcase": ["error", {"properties": "always"}],
    "capitalized-comments": ["error", "always", {"ignoreConsecutiveComments": true}],
    "comma-dangle": ["error", "only-multiline"],
    "comma-spacing": ["error", {"before": false, "after": true}],
    "comma-style": ["error", "last"],
    "computed-property-spacing": ["error", "never"],
    "consistent-this": "off",
    "eol-last": ["error", "always"],
    "func-call-spacing": ["error", "never"],
    "func-names": ["error", "never"],
    "function-paren-newline": ["error", "never"],
    "implicit-arrow-linebreak": ["error", "beside"],
    "indent": ["error", 2, {"SwitchCase": 1, "MemberExpression": 0, "VariableDeclarator": {"var": 2,"let": 2,"const": 3}, "outerIIFEBody": 1}],
    "key-spacing": ["error", {"beforeColon": false, "afterColon": true, "mode": "minimum"}],
    "keyword-spacing": ["error", {"before": true, "after": true}],
    "line-comment-position": ["error", "above"],
    "linebreak-style": ["error", "unix"],
    "lines-around-comment": ["error", {"beforeBlockComment": true}],
    "lines-between-class-members": ["error", "always"],
    "max-depth": ["error", 5],
    "max-len": "off",
    "max-nested-callbacks": ["error", 5],
    "max-statements-per-line": ["error", {"max": 1}],
    "multiline-ternary": ["error", "always-multiline"],
    "new-cap": "error",
    "new-parens": "error",
    "newline-per-chained-call": ["error", {"ignoreChainWithDepth": 4}],
    "no-array-constructor": "error",
    "no-inline-comments": "error",
    "no-lonely-if": "off",
    "no-mixed-operators": "error",
    "no-multiple-empty-lines": ["error", {"max": 2, "maxEOF": 1}],
    "no-nested-ternary": "error",
    "no-new-object": "error",
    "no-tabs": "error",
    "no-trailing-spaces": "error",
    "no-underscore-dangle": "off",
    "no-unneeded-ternary": "error",
    "no-whitespace-before-property": "error",
    "object-curly-newline": "off",
    "object-curly-spacing": ["error", "never"],
    "one-var": ["error", "never"],
    "padded-blocks": "off",
    "quotes": ["error", "single", {"avoidEscape": true, "allowTemplateLiterals": false}],
    "semi": ["error", "always"],
    "semi-spacing": ["error", {"before": false, "after": true}],
    "semi-style": ["error", "last"],
    "space-before-blocks": ["error", "always"],
    "space-before-function-paren": ["error", {"anonymous": "always", "named": "never", "asyncArrow": "always"}],
    "space-in-parens": ["error", "never"],
    "space-infix-ops": "error",
    "space-unary-ops": ["error", {"words": true, "nonwords": false}],
    "spaced-comment": ["error", "always"],
    "switch-colon-spacing": ["error", {"after": true, "before": false}],
    "template-tag-spacing": ["error", "always"],
    "unicode-bom": ["error", "never"]
  }
}