.eslintrc

{
  "extends": [
    // Only import some AirBNB rules
    // https://github.com/airbnb/javascript/tree/master/packages/eslint-config-airbnb-base/rules
    "airbnb-base"
  ],

  // This is the root eslint file.
  // We should ONLY be using eslint rules specific to this project.
  "root": true,

  // All source code is at least ES6 friendly.
  // Note that this is not the case in the demoapp example pages,
  // which are ES5 compatible and not compiled.
  "env": {
    "es6": true
  },

  "ignorePatterns": ["*e2e-spec.js", "*e2e-test.js"],

  // Need `ecmaVersion: 9` for:
  // - [Object spread syntax](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Spread_syntax#Spread_in_object_literals)
  "parser": "@babel/eslint-parser",

  "parserOptions": {
    "ecmaVersion": 9,
    "sourceType": "module",
    "requireConfigFile": false
  },

  // Add ES6 import plugins
  "plugins": [
    "import"
  ],

  "rules": {
    // require trailing commas in multiline object literals
    "comma-dangle": ["off", {
      "arrays": "never",
      "objects": "never",
      "imports": "never",
      "exports": "never",
      "functions": "never"
    }],

    "no-await-in-loop": "off",

    // Re-enable anonymous/unnamed functions
    // https://eslint.org/docs/rules/func-names
    "func-names": "off",

    // Require modules with a single export to use a default export
    // Will ignore because of https://medium.com/@timoxley/named-exports-as-the-default-export-api-670b1b554f65
    // https://github.com/benmosher/eslint-plugin-import/blob/master/docs/rules/prefer-default-export.md
    "import/prefer-default-export": "off",

    // specify the maximum length of a line in your program
    // https://eslint.org/docs/rules/max-len
    "max-len": ["error", {
      "code": 120,
      "comments": 350,
      "ignoreUrls": true,
      "ignoreComments": false,
      "ignoreRegExpLiterals": true,
      "ignoreStrings": true,
      "ignoreTemplateLiterals": true
    }],

    // disallow use of chained assignment expressions
    // https://eslint.org/docs/rules/no-multi-assign
    "no-multi-assign": ["warn"],

    // disallow multiple empty lines and only one newline at the end
    "no-multiple-empty-lines": ["error", { "max": 1, "maxEOF": 1 }],

    // Don"t allow paramter reassignment
    "no-param-reassign": ["off", {
      "props": true
    }],

    // disallow use of unary operators, ++ and --
    // https://eslint.org/docs/rules/no-plusplus
    "no-plusplus": "off",

    // Allow usage of certain Global values
    "no-restricted-globals": ["warn", {
      "name": "isNaN",
      "message": "Make sure to explore using `Number.isNaN()` instead."
    }],

    // Ignore usage of certain properties:
    // - Math.pow (not really sure why AirBNB doesn"t allow this)
    "no-restricted-properties": ["off", {
      "object": "Math",
      "property": "pow"
    }],

    // set "no-trailing-spaces" to only a warning (this shouldn"t fail builds)
    "no-trailing-spaces": ["warn"],

    // set "no-underscore-dangle" to only a warning (also shouldn"t fail builds)
    "no-underscore-dangle": ["warn"],

    // enforce line breaks between braces
    // https://eslint.org/docs/rules/object-curly-newline
    "object-curly-newline": ["error", {
      "ObjectExpression": {
        "minProperties": 8,
        "multiline": true,
        "consistent": true
      },
      "ObjectPattern": {
        "minProperties": 8,
        "multiline": true,
        "consistent": true
      }
    }],

    // Don"t enforce usage of arrow functions, but warn about them.
    // https://eslint.org/docs/rules/prefer-arrow-callback
    "prefer-arrow-callback": ["warn", {}],

    // Prefer destructuring from arrays and objects
    // https://eslint.org/docs/rules/prefer-destructuring
    "prefer-destructuring": ["off", {
      "VariableDeclarator": {
        "array": false,
        "object": true
      },
      "AssignmentExpression": {
        "array": true,
        "object": true
      }
    }, {
      "enforceForRenamedProperties": false
    }],

    // Don"t enforce extra brackets
    // https://eslint.org/docs/2.0.0/rules/arrow-parensextra
    "arrow-parens": ["error", "as-needed", { "requireForBlockBody": true }],

    // Have operators on same line
    // https://eslint.org/docs/rules/operator-linebreak
    "operator-linebreak": ["error", "after"],
    // Allow js in imports
    "import/extensions": ["off"]
  }
}