index.js

module.exports = {
    "extends": [
      "eslint:recommended",
      "prettier",
    ],
    "parser": "@babel/eslint-parser",
    "parserOptions": {
      "requireConfigFile": false,
      "ecmaVersion": 2018,
    },
    "env": {
      "es6": true,
    },
    "rules": {
      "no-console": ["error", { "allow": ["warn", "error"] }],

      // Best Practices
      "curly":      "error",
      "eqeqeq":     "error",
      "no-eq-null": "error",

      // Variables
      "no-use-before-define": ["error", "nofunc"],

      // Stylistic Issues
      "brace-style":                  ["error", "1tbs", { "allowSingleLine": true }],
      "comma-dangle":                 ["error", "never"],
      "comma-spacing":                "error",
      "comma-style":                  "error",
      "func-call-spacing":            "error",
      "indent":                       ["error", 2, { "SwitchCase": 1, "MemberExpression": 1 }],
      "key-spacing":                  ["error", { "mode": "minimum" }],
      "keyword-spacing":              "error",
      "object-curly-spacing":         ["error", "always"],
      "one-var":                      ["error", "never"],
      "quotes":                       ["error", "single", { "allowTemplateLiterals": true }],
      "semi":                         ["error", "never"],
      "space-before-function-paren":  ["error", {
        "anonymous": "never",
        "named": "never",
        "asyncArrow": "always"
      }],
      "space-infix-ops":              "error",

      // ECMAScript 6
      "arrow-body-style":       ["error", "as-needed"],
      "arrow-parens":           ["error", "as-needed"],
      "arrow-spacing":          "error",
      "no-duplicate-imports":   "error",
      "no-useless-constructor": "error",
      "no-var":                 "error",
      "prefer-const":           "error",
      "prefer-template":        "error",
    }
  }