.eslintrc

{
  "parser": "babel-eslint",
  "env": {
    "browser": true,
    "commonjs": true,
    "es6": true,
    "node": true
  },
  "parserOptions": {
    "ecmaVersion": 6,
    "sourceType": "module",
    "ecmaFeatures": {
      "experimentalObjectRestSpread": true
    }
  },
  "rules": {
    // require function declarations instead of expressions
    "func-style": [
      "warn",
      "declaration",
      {
        "allowArrowFunctions": true
      }
    ],
    // disallow declaration of variables already declared in the outer scope
    // "no-shadow": "warn",

    // require let or const instead of var
    "no-var": "warn",
    "no-unused-vars": "warn",
    "no-console": "error",
    "max-len": [
      "warn",
      120
    ],
    // require or disallow use of semicolons instead of ASI
    "semi": [
      "warn",
      "never"
    ],
    // require the use of === and !== except null comparison
    "eqeqeq": [
      "warn",
      "smart"
    ],
    // specify whether double or single quotes should be used
    "quotes": [
      "warn",
      "single",
      "avoid-escape"
    ],
    // require space before/after arrow function"s arrow
    "arrow-spacing": [
      "warn",
      {
        "before": true,
        "after": true
      }
    ],
    "arrow-parens": [
      "warn",
      "as-needed"
    ],
    // suggest using of const declaration for variables that are never modified after declared
    "prefer-const": "warn",
    // restrict what can be thrown as an exception
    "no-throw-literal": "warn",
    // disallow Unused Expressions
    "no-unused-expressions": [
      "warn",
      {
        "allowShortCircuit": true
      }
    ],
    // require padding inside curly braces
    "object-curly-spacing": [
      "warn",
      "always"
    ]
  }
}