.eslintrc

{
  parserOptions: {
    ecmaVersion: 5,
    sourceType: "script"
  },

  // To minimize dependencies on Node- or browser-specific features, leave the
  // env empty, and instead define globals as needed.
  "env": {},
  "extends": "google",

  // Project-wide globals. If other globals are necessary, prefer putting them
  // in a comment at the top of the file rather than adding them here.
  "globals": {
    "console": true,
    "exports": true,
    "module": true,
    "require": true,
  },
  "plugins": [
    "camelcase-ohm",
    "no-extension-in-require",
    "tape"
  ],
  rules: {
    arrow-parens: "off",

    // Enforce "one true brace style", allowing start and end braces to be on the same line.
    brace-style: ["error", "1tbs", {allowSingleLine: true}],

    // Turn off the regular camelcase rule, and use a custom rule which
    // allows semantic actions to be named like `RuleName_caseName`.
    camelcase: 0,
    camelcase-ohm/camelcase-ohm: 2,
    comma-dangle: ["error", "never"],  // Disallow trailing commas.

    consistent-this: 0,
    default-case: 0,

    // Allow use of `==` and `!=` only with null.
    eqeqeq: ["error", "allow-null"],

    guard-for-in: 0,

    max-len: ["error", {code: 100, ignoreUrls: true}],
    max-statements-per-line: ["error", {max: 2}],

    // Don't require `new` when calling functions whose name starts with a capital letter.
    new-cap: ["error", {capIsNew: false}],

    no-console: 2,
    no-constant-condition: 0,  // Allow things like `while(true)`.
    no-else-return: 0,  // Allow `else` after a return statement.
    no-eq-null: 0,
    no-invalid-this: 0,  // Allow `this` outside of classes.

    // Don't allow require() statements to include the '.js' extension.
    no-extension-in-require/main: 2,

    no-implicit-coercion: 0,
    no-negated-condition: 0,
    no-nested-ternary: 0,

    // Allow unused parameters, but not unused variables.
    no-unused-vars: ["error", {vars: "all", args: "none"}],

    no-warning-comments: ["error", {terms: ["xxx", "fixme"]}],

    operator-linebreak: ["error", "after", {overrides: { ":": "ignore", "?": "ignore"}}],
    padded-blocks: 0,
    quotes: ["error", "single", "avoid-escape"],
    radix: 0,
    require-jsdoc: 0,

    "strict": ["error", "global"],

    tape/no-only-test: 2,  // Don't allow `test.only`

    // We would use `["error", "never", {exceptRange: true}]` here, but it doesn't seem to work.
    yoda: 0,

    // The following rules suggest replacing certain patterns with ES6 features.
    // They are disabled for now, but we should consider enabling them if/when we move to ES6.
    no-var: 0,  // Allow the `var` keyword.
    prefer-rest-params: 0,
    prefer-spread: 0
  }
}