.eslintrc.json

{
  "extends": "airbnb-base",
  "env": {
    "node": true
  },
  "parserOptions": {
    "ecmaVersion": 6,

    // Airbnb preset sets this to "module"
    // but everything outside of lib is a script
    "sourceType": "script"
  },
  "rules": {
    // Have to override the airbnb rules, which want training commas for function
    // arguments, even though these are only supported in ES2017 and up.
    // Overriding this rule involves setting all of the same options except for
    // "functions". https://github.com/eslint/eslint/issues/7851#issuecomment-270428874
    "comma-dangle": ["warn", {
      "arrays": "always-multiline",
      "objects": "always-multiline",
      "imports": "always-multiline",
      "exports": "always-multiline",
      "functions": "never" // This is the actual change from the airbnb rules
    }],

    // The Airbnb style guide says nothing about using console,
    // and we legitimately need it for output
    "no-console": "off",

    // Airbnb sets this to "never" even though their written style guide
    // never actually mentions it. Babel inserts it for them, but we're
    // not using Babel.
    "strict": ["error", "safe"],

    // The Airbnb style guide never mentions this, but the airbnb eslint rules
    // consider it an error. Shadowing is a useful language feature, and now
    // that we have lexical scoping, it's not as dangerous as it once was.
    "no-shadow": "off"
  }
}