.eslintrc.js

module.exports = {
  env: {
    browser: true,
    es6: true,
    node: true
  },
  extends: "eslint:recommended",
  parser: "babel-eslint",
  parserOptions: {
    ecmaVersion: 2017,
    sourceType: "module"
  },
  rules: {
    eqeqeq: "error",
    "no-extra-parens": [
      "error",
      "all",
      {
        nestedBinaryExpressions: false
      }
    ],
    "no-inner-declarations": ["error", "both"],
    "valid-jsdoc": "error",
    "block-scoped-var": "error",
    "consistent-return": "error",
    "default-case": "error",
    "dot-notation": "error",
    "no-alert": "error",
    "no-case-declarations": "error",
    "no-eq-null": "warn",
    "no-eval": "warn",
    "no-extra-bind": "warn",
    "no-floating-decimal": "warn",
    "no-implicit-globals": "warn",
    "no-lone-blocks": "warn",
    "no-loop-func": "warn",
    "no-multi-spaces": "warn",
    "no-new": "warn",
    "no-new-func": "warn",
    "no-new-wrappers": "warn",
    "no-self-compare": "warn",
    "no-unused-expressions": "warn",
    "no-useless-call": "warn",
    "no-useless-concat": "warn",
    "vars-on-top": "warn",
    "no-use-before-define": [
      "warn",
      {
        functions: false
      }
    ],
    "array-bracket-spacing": "warn",
    "block-spacing": ["warn", "never"],
    "brace-style": "warn",
    camelcase: "warn",
    "comma-dangle": "warn",
    "comma-spacing": "warn",
    "comma-style": "warn",
    "computed-property-spacing": "warn",
    "eol-last": "warn",
    indent: [
      "warn",
      2,
      {
        SwitchCase: 1
      }
    ],
    "key-spacing": "warn",
    "keyword-spacing": "warn",
    "linebreak-style": "warn",
    "max-len": [
      "warn",
      120,
      {
        ignoreTrailingComments: true,
        ignoreUrls: true,
        ignoreStrings: true
      }
    ],
    "new-cap": [
      "warn",
      {
        capIsNew: false
      }
    ],
    "no-lonely-if": "warn",
    "no-multiple-empty-lines": [
      "warn",
      {
        max: 1,
        maxEOF: 1
      }
    ],
    "no-plusplus": "warn",
    "func-call-spacing": "error",
    "no-trailing-spaces": "warn",
    "no-unneeded-ternary": "warn",
    "no-nested-ternary": "error",
    "no-whitespace-before-property": "warn",
    "object-curly-spacing": "warn",
    "one-var": ["warn", "never"],
    "one-var-declaration-per-line": "warn",
    "operator-linebreak": ["warn", "after"],
    "quote-props": ["warn", "as-needed"],
    quotes: [
      "error",
      "single",
      {
        avoidEscape: true,
        allowTemplateLiterals: true
      }
    ],
    "semi-spacing": "warn",
    semi: "warn",
    "space-before-blocks": "warn",
    "space-in-parens": "warn",
    "space-infix-ops": "warn",
    "arrow-parens": "warn",
    "arrow-spacing": "warn",
    "no-duplicate-imports": "warn",
    "template-curly-spacing": "warn",
    curly: "error",
    "no-var": "warn",
    "prefer-const": "warn",
    "space-before-function-paren": [
      "warn",
      {
        named: "never"
      }
    ]
  },
  overrides: [
    // node files
    {
      files: [
        ".template-lintrc.js",
        "ember-cli-build.js",
        "testem.js",
        "blueprints/*/index.js",
        "config/**/*.js",
        "lib/*/index.js"
      ],
      parserOptions: {
        sourceType: "script",
        ecmaVersion: 2015
      },
      env: {
        browser: false,
        node: true
      }
    }
  ]
};