.eslintrc.json

{
  "root": true,
  "env": {
    "node": true,
    "es6": true
  },
  "extends": [
    "eslint:recommended",
    "plugin:react/recommended"
  ],
  "parser": "babel-eslint",
  "parserOptions": {
    "ecmaFeatures": {
      "jsx": true,
      "modules": true,
      "destructuring": true,
      "experimentalObjectRestSpread": true,
      "spread": true
    },
    "ecmaVersion": 8
  },
  "globals": {
    "document": true,
    "before": true,
    "beforeEach": true,
    "describe": true,
    "it": true,
    "fetch": true,
    "window": true,
    "navigator": true,
    "URL": true
  },
  /**
   * ESLint rules
   *
   * All available rules: http://eslint.org/docs/rules/
   *
   * Rules take the following form:
   *   "rule-name", [severity, { opts }]
   * Severity: 2 == error, 1 == warning, 0 == off.
   */
  "rules": {
    /**
     * Enforced rules
     */
    // syntax preferences
    "quotes": [
      2,
      "single",
      {
        "avoidEscape": true,
        "allowTemplateLiterals": true
      }
    ],
    "semi": 2,
    "no-extra-semi": 2,
    "comma-style": [
      2,
      "last"
    ],
    "wrap-iife": [
      2,
      "inside"
    ],
    "spaced-comment": [
      2,
      "always",
      {
        "markers": [
          "*"
        ]
      }
    ],
    "eqeqeq": [
      2
    ],
    "arrow-body-style": [
      2,
      "as-needed"
    ],
    "accessor-pairs": [
      2,
      {
        "getWithoutSet": false,
        "setWithoutGet": false
      }
    ],
    "curly": [
      2,
      "all"
    ],
    "new-parens": 2,
    "func-call-spacing": 2,
    "arrow-parens": [
      2,
      "always"
    ],
    // anti-patterns
    "no-var": 2,
    "no-with": 2,
    "no-multi-str": 2,
    "no-caller": 2,
    "no-implied-eval": 2,
    "no-labels": 2,
    "no-new-object": 2,
    "no-octal-escape": 2,
    "no-self-compare": 2,
    "no-shadow-restricted-names": 2,
    "no-cond-assign": 2,
    "no-debugger": 2,
    "no-dupe-keys": 2,
    "no-duplicate-case": 2,
    "no-empty-character-class": 2,
    "no-unreachable": 2,
    "no-unsafe-negation": 2,
    "radix": 2,
    "valid-typeof": 2,
    "no-undef": "error",
    "no-unused-vars": [
      2,
      {
        "args": "after-used",
        "vars": "local"
      }
    ],
    // es2015 features
    "require-yield": 2,
    "template-curly-spacing": [
      2,
      "never"
    ],
    // spacing details
    "space-infix-ops": 2,
    "space-in-parens": [
      2,
      "never"
    ],
    "space-before-function-paren": [
      2,
      {
        "anonymous": "always",
        "named": "never",
        "asyncArrow": "always"
      }
    ],
    "no-whitespace-before-property": 2,
    "keyword-spacing": [
      2,
      {
        "overrides": {
          "if": {
            "after": true
          },
          "else": {
            "after": true
          },
          "for": {
            "after": true
          },
          "while": {
            "after": true
          },
          "do": {
            "after": true
          },
          "switch": {
            "after": true
          },
          "return": {
            "after": true
          }
        }
      }
    ],
    "arrow-spacing": [
      2,
      {
        "after": true,
        "before": true
      }
    ],
    // file whitespace
    "no-multiple-empty-lines": [
      2,
      {
        "max": 2
      }
    ],
    "no-mixed-spaces-and-tabs": 2,
    "no-trailing-spaces": 2,
    "linebreak-style": [
      2,
      "unix"
    ],
    "indent": [
      2,
      2,
      {
        "SwitchCase": 1,
        "CallExpression": {
          "arguments": 1
        },
        "MemberExpression": 1
      }
    ],
    /**
     * Disabled, aspirational rules
     */
    // brace-style is disabled, as eslint cannot enforce 1tbs as default, but allman for functions
    "brace-style": [
      0,
      "allman",
      {
        "allowSingleLine": true
      }
    ],
    // key-spacing is disabled, as some objects use value-aligned spacing, some not.
    "key-spacing": [
      0,
      {
        "beforeColon": false,
        "afterColon": true,
        "align": "value"
      }
    ],
    // quote-props is diabled, as property quoting styles are too varied to enforce.
    "quote-props": [
      0,
      "as-needed"
    ],
    // no-implicit-globals will prevent accidental globals
    "no-implicit-globals": [
      0
    ],
    "react/prop-types": [
      1,
      {
        "skipUndeclared": true
      }
    ],
    "react/display-name": [0, { "ignoreTranspilerName": false }]
  },
  "plugins": [
    "react"
  ]
}