.eslintrc.json

{
  "root": true,
  "parserOptions": {
    "ecmaVersion": 9,
    "ecmaFeatures": {
      "jsx": true
    },
    "sourceType": "module"
  },
  "env": {
    "es6": true,
    "node": true,
    "browser": true,
    "jest/globals": true
  },
  "plugins": ["jest"],
  "globals": {
    "document": false,
    "navigator": false,
    "window": false
  },
  "rules": {
    "accessor-pairs": "error",
    "arrow-spacing": [
      "error",
      {
        "before": true,
        "after": true
      }
    ],
    "block-spacing": [
      "error",
      "always"
    ],
    "brace-style": [
      "error",
      "1tbs",
      {
        "allowSingleLine": true
      }
    ],
    "camelcase": [
      "error",
      {
        "properties": "never"
      }
    ],
    "comma-dangle": [
        "error", "always-multiline"
    ],
    "comma-spacing": [
      "error",
      {
        "before": false,
        "after": true
      }
    ],
    "comma-style": [
      "error",
      "last"
    ],
    "constructor-super": "error",
    "curly": [
      "error",
      "multi-line"
    ],
    "dot-location": [
      "error",
      "property"
    ],
    "eol-last": "error",
    "eqeqeq": [
      "error",
      "always",
      {
        "null": "ignore"
      }
    ],
    "func-call-spacing": [
      "error",
      "never"
    ],
    "generator-star-spacing": [
      "error",
      {
        "before": true,
        "after": true
      }
    ],
    "handle-callback-err": [
      "error",
      "^(err|error)$"
    ],
    "indent": [
      "error",
      4,
      {
        "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
      }
    ],
    "new-cap": [
      "error",
      {
        "newIsCap": true,
        "capIsNew": false
      }
    ],
    "new-parens": "error",
    "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-delete-var": "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-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-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",
      {
        // This doesn't allow functions to be declared as a single line
        // https://github.com/eslint/eslint/issues/7145#issuecomment-281882639
        // "blocks": "always",
        "switches": "always",
        "classes": "always"
      }
    ],
    "prefer-promise-reject-errors": "error",
    "prefer-const": "error",
    "quotes": [
      "error",
      "single",
      {
        "avoidEscape": true,
        "allowTemplateLiterals": true
      }
    ],
    "rest-spread-spacing": [
      "error",
      "never"
    ],
    "semi": [
      "error",
      "always"
    ],
    "semi-spacing": [
      "error",
      {
        "before": false,
        "after": true
      }
    ],
    "space-before-blocks": [
      "error",
      "always"
    ],
    "space-before-function-paren": [
      "error",
      "never"
    ],
    "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",
      "always"
    ],
    "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"
    ]
  }
}