@zemd/eslint-js

Shared ESLint config for JavaScript projects

This package includes a set of ESLint configurations for JavaScript projects.

The package includes:

Package	Description	Rules	License
eslint-config-flat-gitignore	ignores all files from your .gitignore file		MIT
@eslint/js	standard ESLint rules	recommended plus hand-picked rules that were not included	MIT
eslint-plugin-unicorn	modern set of rules	I think pretty opinionated, so I carefully hand-picked rules, avoiding style related rules	MIT
eslint-plugin-sonarjs	(Optional) ESLint plugin maintained by Sonar, designed to help developers write Clean Code	all recommended rules minus some disabled for better DX (auto-enabled when installed)	LGPL-3.0-only
@eslint-community/eslint-plugin-eslint-comments	additional ESLint rules for ESLint directive comments (e.g. //eslint-disable-line)	recommended rules	MIT
@eslint/json	plugin that allows you to natively lint JSON and JSONC	recommended rules minus the sort-keys	Apache-2.0
eslint-plugin-regexp	ESLint plugin for finding RegExp mistakes	recommended rules	MIT

Installation

npm install --save-dev @zemd/eslint-js

Usage

// eslint.config.js

import javascript from "@zemd/eslint-js";
export default [...javascript()];

Configuring environments (globals)

By default every file is linted with the "all" environment, meaning both Node.js and browser globals are available (great for isomorphic code). You can change the default environment with the env option:

import javascript from "@zemd/eslint-js";

// A browser-only app
export default [...javascript({ env: "browser" })];

Available presets:

env	Globals
"all"	Node.js and browser globals (default)
"node"	Node.js globals only (process, Buffer, __dirname, …)
"browser"	browser globals only (window, document, navigator, …)
"none"	no runtime globals (only the base language globals)

The base language globals are always included regardless of the selected environment, and by default they stay in sync with ecmaVersion — so ecmaVersion: 2024 uses the es2024 globals, and ecmaVersion: "latest" uses the newest available preset. Override them explicitly with languageGlobals (any preset from the globals package, e.g. "es2020", "es2024", "builtin", or "latest"):

import javascript from "@zemd/eslint-js";

// Parse 2024 syntax; globals default to es2024 automatically.
export default [...javascript({ ecmaVersion: 2024 })];

// …or pin the globals independently of the syntax level.
export default [...javascript({ ecmaVersion: 2024, languageGlobals: "latest" })];

You can also pass a raw globals record for custom runtimes (e.g. web workers, Deno, Bun):

import globals from "globals";
import javascript from "@zemd/eslint-js";

export default [...javascript({ env: { ...globals.worker } })];

Monorepos: different environments per package

When @zemd/eslint-js is used from the root of a monorepo, individual packages often target different runtimes — some are Node.js-only, some are browser-only, and some are mixed. Use overrides to map paths to environments. Anything not matched by an override falls back to the default env, and each file resolves to exactly one environment (a node package will not leak browser globals, and vice versa):

import javascript from "@zemd/eslint-js";

export default [
  ...javascript({
    // Fallback for everything not matched below (e.g. shared/isomorphic code).
    env: "all",
    overrides: [
      { files: ["packages/server/**", "apps/api/**"], env: "node" },
      { files: ["packages/ui/**", "apps/web/**"], env: "browser" },
      // Extend a preset with extra globals for a specific package:
      { files: ["packages/worker/**"], env: "node", globals: { EdgeRuntime: "readonly" } },
    ],
  }),
];

Use a trailing /** (e.g. packages/server/**) so the pattern matches every file inside the package directory.

Custom globals passed via the top-level globals option are merged into every environment (the default env and each override):

import javascript from "@zemd/eslint-js";

export default [
  ...javascript({
    globals: { myGlobal: "readonly" },
  }),
];

SonarJS rules (optional)

To stay compliant with enterprise policies that forbid LGPL software, SonarJS rules are optional. If you want to use them, install eslint-plugin-sonarjs and the rules will be detected and enabled automatically.

You might be also interested in

Package	Version	Description
@zemd/eslint-js		JavaScript-only rules.
@zemd/eslint-ts		TypeScript rules (includes JS rules from @zemd/eslint-js).
@zemd/eslint-react		React rules (includes TS rules from @zemd/eslint-ts and JS rules from @zemd/eslint-js).
@zemd/eslint-rock-stack		Rules for Fullstack projects that include React.js, GraphQL, Playwright, Tailwind(optional), Turbo, Vitest, and Storybook.
@zemd/eslint-next		Rules for Next.js projects (inherits from @zemd/eslint-rock-stack).
@zemd/eslint-astro		Rules for Astro based projects (includes rules @zemd/eslint-react by default).

License

The @zemd/eslint-js is licensed under Apache-2.0 license .

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