.eslintrc.json

{
    "parserOptions": {
        "ecmaVersion": 9,
        "sourceType": "module",
        "ecmaFeatures": {
            "jsx": true
        }
    },
    "env": {
      "browser": true,
      "es6": true,
      "webextensions": true,
      "commonjs": true
    },
    "rules": {
        "arrow-spacing": ["error", { "before": true, "after": true }],
        "block-spacing": ["error", "always"],
        "brace-style": ["error", "1tbs", { "allowSingleLine": true }],
        "comma-spacing": ["error", { "before": false, "after": true }],
        "comma-style": ["error", "first"],
        "eqeqeq": ["error", "always", { "null": "ignore" }],
        "func-call-spacing": ["error", "never"],
        "indent": ["error", 2, {
          "SwitchCase": 1,
          "VariableDeclarator": 1,
          "outerIIFEBody": 1,
          "MemberExpression": 1,
          "FunctionDeclaration": { "parameters": 1, "body": 1 },
          "FunctionExpression": { "parameters": 1, "body": 1 },
          "CallExpression": { "arguments": 1 },
          "ArrayExpression": 1,
          "ObjectExpression": 1,
          "ImportDeclaration": 1,
          "flatTernaryExpressions": false,
          "ignoreComments": false
        }],
        "key-spacing": ["error", { "beforeColon": false, "afterColon": true }],
        "keyword-spacing": ["error", { "before": true, "after": true }],
        "no-array-constructor": "error",
        "no-caller": "error",
        "no-class-assign": "error",
        "no-compare-neg-zero": "error",
        "no-cond-assign": "error",
        "no-const-assign": "error",
        "no-constant-condition": ["error", { "checkLoops": false }],
        "no-control-regex": "error",
        "no-debugger": "error",
        "no-dupe-args": "error",
        "no-dupe-class-members": "error",
        "no-dupe-keys": "error",
        "no-duplicate-case": "error",
        "no-empty-character-class": "error",
        "no-empty-pattern": "error",
        "no-eval": "error",
        "no-ex-assign": "error",
        "no-extend-native": "error",
        "no-extra-bind": "error",
        "no-extra-boolean-cast": "error",
        "no-extra-parens": ["error", "functions"],
        "no-fallthrough": "error",
        "no-floating-decimal": "error",
        "no-func-assign": "error",
        "no-global-assign": "error",
        "no-implied-eval": "error",
        "no-inner-declarations": ["error", "functions"],
        "no-invalid-regexp": "error",
        "no-irregular-whitespace": "error",
        "no-iterator": "error",
        "no-label-var": "error",
        "no-labels": ["error", { "allowLoop": false, "allowSwitch": false }],
        "no-lone-blocks": "error",
        "no-mixed-operators": ["error", {
          "groups": [
            ["==", "!=", "===", "!==", ">", ">=", "<", "<="],
            ["&&", "||"],
            ["in", "instanceof"]
          ],
          "allowSamePrecedence": true
        }],
        "no-mixed-spaces-and-tabs": "error",
        "no-multi-spaces": "error",
        "no-multi-str": "error",
        "no-multiple-empty-lines": ["error", { "max": 1, "maxEOF": 0 }],
        "no-negated-in-lhs": "error",
        "no-new": "error",
        "no-new-func": "error",
        "no-new-object": "error",
        "no-new-require": "error",
        "no-new-symbol": "error",
        "no-new-wrappers": "error",
        "no-obj-calls": "error",
        "no-octal": "error",
        "no-octal-escape": "error",
        "no-path-concat": "error",
        "no-proto": "error",
        "no-redeclare": "error",
        "no-regex-spaces": "error",
        "no-return-assign": ["error", "except-parens"],
        "no-return-await": "error",
        "no-self-assign": "error",
        "no-self-compare": "error",
        "no-sequences": "error",
        "no-shadow-restricted-names": "error",
        "no-sparse-arrays": "error",
        "no-tabs": "error",
        "no-template-curly-in-string": "error",
        "no-this-before-super": "error",
        "no-throw-literal": "error",
        "no-trailing-spaces": "error",
        "no-undef": "error",
        "no-undef-init": "error",
        "no-unexpected-multiline": "error",
        "no-unmodified-loop-condition": "error",
        "no-unneeded-ternary": ["error", { "defaultAssignment": false }],
        "no-unreachable": "error",
        "no-unsafe-finally": "error",
        "no-unsafe-negation": "error",
        "no-unused-expressions": ["error", { "allowShortCircuit": true, "allowTernary": true, "allowTaggedTemplates": true }],
        "no-unused-vars": ["error", { "vars": "all", "args": "none", "ignoreRestSiblings": true }],
        "no-use-before-define": ["error", { "functions": false, "classes": false, "variables": false }],
        "no-useless-call": "error",
        "no-useless-computed-key": "error",
        "no-useless-constructor": "error",
        "no-useless-escape": "error",
        "no-useless-rename": "error",
        "no-useless-return": "error",
        "no-whitespace-before-property": "error",
        "no-with": "error",
        "object-property-newline": ["error", { "allowMultiplePropertiesPerLine": true }],
        "operator-linebreak": ["error", "after", { "overrides": { "?": "before", ":": "before" } }],
        "padded-blocks": ["error", { "blocks": "never", "switches": "never", "classes": "never" }],
        "prefer-promise-reject-errors": "error",
        "quotes": ["error", "single", { "avoidEscape": true, "allowTemplateLiterals": true }],
        "rest-spread-spacing": ["error", "never"],
        "semi": ["error", "never"],
        "semi-spacing": ["error", { "before": false, "after": true }],
        "space-before-blocks": ["error", "always"],
        "space-before-function-paren": ["error", "always"],
        "space-in-parens": ["error", "never"],
        "space-infix-ops": "error",
        "space-unary-ops": ["error", { "words": true, "nonwords": false }],
        "spaced-comment": ["error", "always", {
          "line": { "markers": ["*package", "!", "/", ",", "="] },
          "block": { "balanced": true, "markers": ["*package", "!", ",", ":", "::", "flow-include"], "exceptions": ["*"] }
        }],
        "symbol-description": "error",
        "template-curly-spacing": ["error", "never"],
        "template-tag-spacing": ["error", "never"],
        "unicode-bom": ["error", "never"],
        "use-isnan": "error",
        "valid-typeof": ["error", { "requireStringLiterals": true }],
        "wrap-iife": ["error", "any", { "functionPrototypeMethods": true }],
        "yield-star-spacing": ["error", "both"],
        "yoda": ["error", "never"]
    }
}