@hughescr/eslint-config-default

Shared ESLint flat config for JavaScript and TypeScript projects. Bundles a curated set of plugins and enforces consistent style, correctness, and type-safety rules out of the box.

• ESLint v10, ESM module
• BSD-3-Clause license

Installation

eslint is included as a dependency, so you do not need to install it separately.

bun add -D @hughescr/eslint-config-default

Usage

Create an eslint.config.mjs in your project root:

import hughescrDefault from '@hughescr/eslint-config-default';
import { defineConfig } from 'eslint/config';

export default defineConfig(
    ...hughescrDefault,
    // your project-specific overrides here
);

The package exports a complete flat config array. Spread it into defineConfig() and add any project-specific overrides after it.

What's Included

The following plugins are bundled and pre-configured:

• @eslint/js — core ESLint rules
• @stylistic/eslint-plugin — formatting rules
• typescript-eslint — TypeScript support with type-checked rules
• eslint-plugin-import-x — import ordering and hygiene
• eslint-plugin-unicorn — opinionated best practices
• eslint-plugin-sonarjs — code quality and cognitive complexity
• eslint-plugin-lodash — Lodash usage patterns
• eslint-plugin-n — Node.js-specific rules
• eslint-plugin-promise — Promise best practices
• eslint-plugin-regexp — regular expression correctness
• @eslint-community/eslint-plugin-eslint-comments — lint comment hygiene
• eslint-plugin-package-json — package.json validation
• @hughescr/eslint-plugin-test-hygiene — test-file hygiene rules (see below)
• @hughescr/eslint-plugin-module-boundaries — module boundary integrity rules (see below)

Custom Rules

@hughescr/eslint-plugin-test-hygiene

Four rules enforced at error severity on all files. Docs: docs/rules/

Rule	Severity	Description
@hughescr/test-hygiene/no-mock-module-in-test-body	error	mock.module() calls must live only in setup files, not inside describe/it blocks
@hughescr/test-hygiene/require-fake-timers-cleanup	error	Every jest.useFakeTimers() must be paired with jest.useRealTimers() in a cleanup hook
@hughescr/test-hygiene/require-mock-cleanup	error	Every jest.spyOn() must be paired with jest.restoreAllMocks() or mockRestore() in afterEach
@hughescr/test-hygiene/require-mock-reset	error	Mocks imported from configured setup modules must have their reset helper called in afterEach

@hughescr/eslint-plugin-module-boundaries

Three rules for TypeScript projects. Docs: docs/rules/

Rule	Severity	Description
@hughescr/module-boundaries/no-internal-in-barrel	error	Barrel index.ts files must not re-export @internal-tagged symbols
@hughescr/module-boundaries/no-star-export-from-non-barrel	error	Barrel index.ts files must not use export * from './x' for non-barrel files
@hughescr/module-boundaries/no-cross-module-internal	off	Production code must not import @internal symbols from a different module — requires a modules option; off by default

Enabling no-cross-module-internal

This rule requires a project-specific modules option that describes your architectural module layout. Add an override after spreading this config:

import hughescrDefault from '@hughescr/eslint-config-default';
import { defineConfig } from 'eslint/config';

export default defineConfig(
    ...hughescrDefault,
    {
        rules: {
            '@hughescr/module-boundaries/no-cross-module-internal': ['error', {
                modules: [
                    { name: 'agent',   pattern: 'src/agent/**' },
                    { name: 'storage', pattern: 'src/storage/**' },
                    // … one entry per architectural module
                ],
            }],
        },
    },
);

The modules array defines which directory trees form distinct boundaries. Imports of @internal-tagged symbols that cross those boundaries are flagged as errors.

Key Style Choices

• 4-space indentation
• Single quotes, semicolons required
• Most rules use warn severity; error is reserved for critical correctness issues
• eslint-disable comments must include a description

TypeScript Support

TypeScript rules are applied automatically to .ts, .tsx, .cts, and .mts files using typescript-eslint's type-checked configs. The buildTypescriptExtensionRules function automatically promotes applicable core ESLint rules to their @typescript-eslint equivalents.

Type-checked rules require a tsconfig.json in your project root. The config uses:

parserOptions: {
    projectService: true,
    tsconfigRootDir: process.cwd(),
}

If your project has no tsconfig.json, TypeScript files will still be linted but type-aware rules will be skipped.

Developer

To browse the full config interactively, inspect enabled/disabled rules, or find unconfigured rules:

bun rules-checkup