bfx-lint-js

ESLint rules applied on the Bitfinex codebase, with ESLint itself bundled in.

Installing this package installs one package. It resolves nothing from the registry at install time: a reviewed, pinned copy of ESLint lives in vendor/ and ships inside the tarball. The rule set is built entirely from rules in ESLint core — no plugins, no shared configs — so there is no plugin graph to audit either.

The house style, in short: 2-space indent, single quotes, no semicolons, no trailing commas, a space before function parens, === everywhere except against null, and const over let over var.

Install

npm i -D @bitfinex/lint-js

No eslint install, and no eslint.config.js to write.

Usage

npx bfx-lint-js .
npx bfx-lint-js . --fix

Or as scripts:

"scripts": {
  "lint": "bfx-lint-js .",
  "lint:fix": "bfx-lint-js . --fix"
}

With no paths given, bfx-lint-js lints ..

CLI options

Option	Description
--fix	Write fixes to disk.
--esm	Treat .js as ES modules. Implied when your package.json has "type": "module".
--mocha	Add Mocha globals to test/**/*.js, **/*.test.js and **/*.spec.js.
--format <name>	Output format (default: stylish). Any ESLint formatter, e.g. json, compact.
--max-warnings <n>	Exit non-zero past this many warnings (default: -1, off).
--no-config	Ignore any eslint.config.js and use the built-in config.
-v, --version	Print the bfx-lint-js and vendored ESLint versions.
-h, --help	Print usage.

Exit codes: 0 clean, 1 lint errors (or warnings past --max-warnings), 2 bad usage or a crash.

If your project has an eslint.config.js, it wins — bfx-lint-js runs it instead of the built-in config. Pass --no-config to force the built-in one.

Usage as a config

To customise the rules, write an eslint.config.js and bfx-lint-js will pick it up:

'use strict'

const setup = require('@bitfinex/lint-js')

module.exports = setup()

setup() returns a flat-config array. Append your own config objects to it when you need to layer on something the options below don't cover:

module.exports = [
  ...setup({ mocha: true }),
  { files: ['scripts/**/*.js'], rules: { 'no-console': 'off' } }
]

ESM projects

The package is CommonJS, which ESM imports fine. In a project with "type": "module" — or in an eslint.config.mjs — use a default import:

import setup from '@bitfinex/lint-js'

export default setup({ esm: true })

Subpath imports need the .js extension. ESM does not infer extensions the way require does, so @bitfinex/lint-js/lib/ignores fails to resolve:

import { defaultIgnores } from '@bitfinex/lint-js/lib/ignores.js'

export default setup({ esm: true, ignores: [...defaultIgnores, 'generated/'] })

Running bfx-lint-js with no config file at all also works: it reads your package.json and turns on esm for you when "type": "module" is set.

Options

setup({
  files: ['**/*.js', '**/*.cjs', '**/*.mjs'],
  ignores: ['**/dist/', '**/build/', '**/coverage/', '**/vendor/', '**/tmp/', '**/temp/', '**/.cache/', '**/.nyc_output/', '**/*.min.js', '**/bundle.js'],
  globals: {},
  mocha: false,
  esm: false,
  rules: {}
})

Option	Default	Description
files	['**/*.js', '**/*.cjs', '**/*.mjs']	Glob patterns the rules and globals apply to — not a way to scope the run, see below.
ignores	see above	Paths to skip. Replaces the defaults rather than extending them, so re-list any you still want. node_modules is always ignored by ESLint itself.
globals	{}	Extra globals, merged over the built-in Node set. Use the ESLint form: { myGlobal: 'readonly' }.
mocha	false	true applies Mocha globals to test/**/*.js, **/*.test.js and **/*.spec.js. Pass an array of globs to target different paths.
esm	false	Sets the module system for .js files — see below.
rules	{}	Rule overrides, merged over the defaults.

What files selects

files picks which files the rules and globals attach to, not which files are linted. ESLint globs .js, .cjs and .mjs on its own, so narrowing files takes nothing out of the run — it leaves those files with no rules, and a file with no rules always passes:

setup({ files: ['src/**/*.js'] })

// src/a.js   linted with the full rule set
// src/b.cjs  linted with no rules — reports nothing
// other/d.js linted with no rules — reports nothing

To limit what gets linted, use ignores, or pass the paths on the command line: bfx-lint-js src.

Module system

esm only governs .js, the one extension where the module system is ambiguous. .cjs and .mjs are always parsed according to their extension, regardless of the flag:

Extension	esm: false (default)	esm: true
.js	CommonJS	ES module
.cjs	CommonJS	CommonJS
.mjs	ES module	ES module

Under esm: true, a .js file using require/module.exports reports no-undef — that is intended, since you have declared .js to be ESM. Put CommonJS code in .cjs.

Examples

// ESM project with Mocha tests
module.exports = setup({ esm: true, mocha: true })

// Browser-ish globals and a couple of relaxed rules
module.exports = setup({
  globals: { window: 'readonly', document: 'readonly' },
  rules: { 'no-console': 'off', camelcase: 'off' }
})

// Keep the default ignores and add one
const { defaultIgnores } = require('@bitfinex/lint-js/lib/ignores')
module.exports = setup({ ignores: [...defaultIgnores, 'generated/'] })

Requirements

Node 16 or newer. Tested on 16.20.2 and 24.20.0.

What ships inside

vendor/ holds ESLint 8.57.1 and its 99 dependencies, committed to the repo and published in the tarball. Consequences worth knowing:

• Nothing is resolved at install time. The tree you review is the tree that runs. None of the 99 packages declares an install, preinstall or postinstall script, so nothing executes when you install.
• The ESLint version is frozen and only changes when this package is upgraded and re-reviewed. That also pins the rule set: the formatting rules (indent, quotes, semi, …) that later ESLint releases moved out to ESLint Stylistic are still present here and will not disappear underneath you.
• 8.57.1 is end-of-life and receives no upstream security patches. It is the last ESLint line that supports Node 16 — newer releases require Node 20.19+. If the Node 16 floor is ever dropped, the vendored copy should move to a maintained release.
• Third-party licenses are reproduced in THIRD-PARTY-NOTICES.md.

License

MIT