.eslintrc.json

{
  "extends": [
    "airbnb",
    "eslint:recommended",
    "plugin:jsx-a11y/recommended",
    "plugin:react/recommended"
  ],
  "plugins": [
    "babel",
    "import",
    "jsx-a11y",
    "react"
  ],
  "parserOptions": {
    "ecmaVersion": 2018,
    "sourceType": "module",
    "ecmaFeatures": {
      "jsx": true
    }
  },
  "env": {
    "browser": true,
    "es6": true,
    "node": true,
    "jest": true
  },
  "globals": {
    "before": true,
    "spyOn": true,
    "__PATH_PREFIX__": true,
    "__BASE_PATH__": true,
    "__ASSET_PREFIX__": true
  },
  "rules": {
    "react/jsx-filename-extension": [1, { "extensions": [".js", ".jsx"] }],
    "react/jsx-one-expression-per-line": ["off"],
    "react/jsx-props-no-spreading": ["error", { "exceptions": ["svg"] }],
    "no-unused-expressions": ["error", { "allowTaggedTemplates": true }],
    "no-var": "error",
    "no-unused-vars": 1,
    "arrow-spacing": ["error", { "before": true, "after": true }],
    "indent": ["error", 2],
    "semi": ["error", "never"],
    "max-len": ["error", {"ignoreTemplateLiterals": true, "ignoreStrings": true}],
    "comma-dangle": ["error", {
        "arrays": "always-multiline",
        "objects": "always-multiline",
        "imports": "always-multiline",
        "exports": "always-multiline",
        "functions": "ignore"
    }],
    "template-curly-spacing": ["error", "always"],
    "arrow-parens": ["error", "as-needed"],
    "linebreak-style": "off",
    "react/prop-types": [
      "error",
      {
        "ignore": [
          "children"
        ]
      }
    ],
    "react/display-name": [
      "off"
    ]
  },
  "overrides": [
    {
      "files": [
        "packages/**/gatsby-browser.js",
        "packages/gatsby/cache-dir/**/*"
      ],
      "env": {
        "browser": true
      },
      "globals": {
        "___loader": false,
        "___emitter": false
      }
    }
  ]
}