.eslintrc.json

{
    "env": {
        "node": true,
        "es6": true
    },
    "globals": {
      "char": false
    },
    "extends": [ "eslint:recommended" ],
    "rules": {
        "indent": [
            "error",
            2
        ],
        "linebreak-style": [
            "error",
            "unix"
        ],
        "quotes": [
            "error",
            "single"
        ],
        "semi": [
            "error",
            "always"
        ],
        "no-shadow-restricted-names": "error",
        "no-shadow": [
          "error",
          { "builtinGlobals": true }
        ],
        "no-var": "error",
        "prefer-const": "error",
        "no-else-return": "error",
        "default-case": "error",
        "consistent-return": "error",
        "no-restricted-syntax": [
            "error",
            {
                "selector": "ForInStatement",
                "message": "for..in loops iterate over the entire prototype chain. Use Object.{keys,values,entries}."
            }
        ]
    }
}