.eslintrc.json

{
  "root": true,
  "parserOptions": {
    "ecmaVersion": 6,
    "sourceType": "script",
    "ecmaFeatures": {
      "impliedStrict": true,
      "jsx": true
    }
  },
  "env": {
    "es6": true
  },
  "globals": {
    "game": false
  },
  "rules": {
    "indent": ["warn", 4],
    "semi": "warn",
    "no-extra-semi": "warn",
    "new-parens": "error",
    "comma-spacing": "warn",
    "semi-spacing": "warn",
    "no-bitwise": "error",
    "no-multi-assign": "warn",
    "no-trailing-spaces": "warn",
    "one-var": ["warn", "never"],
    "semi-style": ["warn", "last"],
    "no-confusing-arrow": ["error", {"allowParens": true}],
    "no-const-assign": "error",
    "no-new-wrappers": "error",
    "no-new-func": "error",
    "no-labels": "error",
    "no-implied-eval": "error",
    "no-extra-label": "error",
    "no-eval": "warn",
    "no-void": "error",
    "no-with": "error",

    "for-direction": "warn",
    "no-cond-assign": "warn",
    "no-return-assign": "warn",
    "no-dupe-args": "warn",
    "no-unsafe-negation": "warn",

    "object-shorthand": ["warn", "never"],
    "no-var": "warn",
    "no-restricted-syntax": [
      "warn",
      {
        "selector": "FunctionDeclaration",
        "message": "Please use `let f = function()` instead of `function f()`"
      },
      {
        "selector": "SequenceExpression",
        "message": "Sorry, `,` may only be used for functions and arrays, you might have meant a `;`?"
      }
    ]
  }
}