.eslintrc.json

{
  "env": {
    "browser": false,
    "node": true,
    "es6": true,
    "mocha": true
  },
  "parserOptions": {
      "ecmaVersion": 8,
      "sourceType": "module",
      "ecmaFeatures": {
          "jsx": true
      }
  },
  "extends": [
    "eslint:recommended"
  ],
  "rules": {
    // Possible Syntax
    "no-console": "warn",
    "no-control-regex": "warn",
    "no-empty": ["error", { "allowEmptyCatch": true }],

    // Best Practices
    "block-scoped-var": "warn",
    "complexity": ["warn", 15],
    "consistent-return": "warn",
    "curly": ["error", "all"],
    "default-case": "error",
    "dot-location": ["error", "property"],
    "dot-notation": "error",
    "eqeqeq": "error",
    "guard-for-in": "warn",
    "no-alert": "warn",
    "no-caller": "error",
    "no-div-regex": "warn",
    "no-else-return": "warn",
    "no-empty-function": ["error", { "allow": ["constructors", "arrowFunctions"] }],
    "no-eval": "warn",
    "no-extra-label": "error",
    "no-floating-decimal": "error",
    "no-implied-eval": "warn",
    "no-invalid-this": "error",
    "no-iterator": "error",
    "no-labels": "error",
    "no-lone-blocks": "error",
    "no-loop-func": "warn",
    "no-multi-spaces": "error",
    "no-multi-str": "error",
    "no-new-func": "warn",
    "no-octal-escape": "error",
    "no-proto": "error",
    "no-return-assign": "warn",
    "no-script-url": "warn",
    "no-self-compare": "error",
    "no-throw-literal": "error",
    "no-unmodified-loop-condition": "warn",
    "no-unused-expressions": "warn",
    "no-useless-call": "error",
    "no-void": "error",
    "no-warning-comments": ["warn", { "terms": ["todo", "fixme", "note"], "location": "start" }],
    "require-await": "warn",
    "yoda": "error",

    // Variables
    "no-delete-var": "warn",
    "no-shadow": "warn",
    "no-shadow-restricted-names": "error",
    "no-undef-init": "error",
    "no-use-before-define": "error",

    // Node.js / CommonJS
    "no-buffer-constructor": "error",
    "no-new-require": "error",
    "no-path-concat": "error",

    // Formatting Rules
    "array-bracket-newline": ["error", { "multiline": true }],
    "array-bracket-spacing": ["warn", "never"],
    "block-spacing": ["error", "always"],
    "brace-style": ["error", "1tbs", { "allowSingleLine": true }],
    "camelcase": ["error", { "properties": "always" }],
    "comma-spacing": ["error", { "before": false, "after": true }],
    "comma-style": ["error", "last"],
    "computed-property-spacing": ["error", "never"],
    "consistent-this": ["error", "self"],
    "eol-last": ["error", "always"],
    "func-call-spacing": ["error", "never"],
    "function-paren-newline": ["error", "multiline"],
    "id-length": ["error", { "min": 2, "max": 40 }],
    "indent": ["error", 2, { "SwitchCase": 1 }],
    "jsx-quotes": ["error", "prefer-double"],
    "key-spacing": ["error", {"afterColon": true, "beforeColon": false, "mode": "minimum"}],
    "keyword-spacing": ["error", {"before": true, "after": true}],
    "linebreak-style": ["error", "unix"],
    "lines-around-comment": ["error", { "beforeBlockComment": true }],
    "lines-between-class-members": ["error", "always"],
    "max-len": ["warn", { "code": 120 }],
    "new-cap": "error",
    "new-parens": "error",
    "newline-per-chained-call": "error",
    "no-array-constructor": "error",
    "no-lonely-if": "error",
    "no-multi-assign": "error",
    "no-multiple-empty-lines": ["error", { "max": 2, "maxEOF": 1, "maxBOF": 1 }],
    "no-new-object": "error",
    "no-tabs": "error",
    "no-unneeded-ternary": "error",
    "no-whitespace-before-property": "error",
    "object-curly-newline": ["error", { "multiline": true }],
    "object-curly-spacing": ["error", "always"],
    "operator-assignment": "warn",
    "operator-linebreak": ["error", "after", { "overrides": { "?": "none", ":": "none" } }],
    "quote-props": ["error", "as-needed"],
    "quotes": ["error", "single"],
    "semi": "error",
    "semi-spacing": ["error", { "before": false, "after": true }],
    "semi-style": ["error", "last"],
    "space-before-blocks": "error",
    "space-before-function-paren": ["error", "never"],
    "space-in-parens": "error",
    "space-infix-ops": "error",
    "space-unary-ops": ["error", { "words": true, "nonwords": false }],
    "spaced-comment": ["warn", "always"],
    "switch-colon-spacing": ["error", {"after": true, "before": false}],
    "template-tag-spacing": "error",

    // ES6 Formatting Rules
    "arrow-body-style": ["error", "always"],
    "arrow-parens": "error",
    "arrow-spacing": ["error", { "before": true, "after": true }],
    "generator-star-spacing": ["error", { "before": true, "after": false }],
    "no-confusing-arrow": "error",
    "no-var": "warn",
    "object-shorthand": ["error", "consistent"],
    "prefer-arrow-callback": "error",
    "prefer-const": "warn",
    "prefer-numeric-literals": "warn",
    "prefer-rest-params": "warn",
    "prefer-spread": "warn",
    "prefer-template": "warn",
    "rest-spread-spacing": "error",
    "symbol-description": "error",
    "template-curly-spacing": "error",
    "yield-star-spacing": ["error", {"before": true, "after": false}]
  }
}