.eslintrc

{
  "extends": "airbnb/base",
  "rules": {
    "strict": [0], // using node but not ES6 modules or Babel so want to use "use strict"
    "no-console": [0], // not applicable -- using node
    "no-else-return": [0], // we like to always use "return" with callback and this makes that more awkward
    "no-param-reassign": [0], // I find this causes more bugs and makes more ugly code than it fixes
    "prefer-spread": [0], // for compatability with <6
    "prefer-rest-params": [0], // for compatability with <6
    "arrow-body-style": ["warn", "as-needed"], // especially in tests, multiline single-return arrow functions are common
    "quote-props": ["error", "consistent-as-needed"],
    "no-restricted-syntax": ["error", "ForInStatement", "LabeledStatement", "WithStatement"]
  },
  "parserOptions": {
    "ecmaVersion": 2018
  },
  "env": {
    "node": true,
    "jest": true
  }
}