@anarkisti/biome-config

Shared Biome configuration — formatter, linter and import sorting in one tool — for Node, React and plain web projects. Biome does not depend on the typescript package, so it never holds back a TypeScript upgrade.

Install

yarn add -D @anarkisti/biome-config @biomejs/biome

Usage

biome.json next to the project's package.json (Biome resolves the preset through it):

{ "extends": ["@anarkisti/biome-config"] }       // Node and plain web projects
{ "extends": ["@anarkisti/biome-config/react"] } // React

// package.json
"scripts": {
  "lint": "biome check src",
  "lint:fix": "biome check --write src"
}

biome check covers formatting, linting and import order in one pass.

What the presets set

• Formatting in Prettier's style: 2 spaces, double quotes, semicolons, trailing commas, 100 columns, LF.
• Linting: Biome's recommended rules, plus unused imports as errors and unused variables as warnings (_-prefixed names are ignored). Non-null assertions are allowed. useButtonType and the a11y interaction rules (noStaticElementInteractions, useKeyWithClickEvents, useSemanticElements, noSvgWithoutTitle, noAutofocus, useMediaCaption) are off for now.
• Imports sorted; type-only imports become import type, mixed ones keep inline type specifiers.
• React (/react): the React domain, and useComponentExportOnlyModules (warn, constant exports allowed) for fast refresh.
  • useExhaustiveDependencies reports missing dependencies but not extra ones: a dependency the effect never reads is usually there to re-run it, and Biome's fix would delete it.
  • The fast-refresh check is off in routes/ and *.test.tsx/*.spec.tsx. File routes keep their components local (the router hot-reloads them), and tests never hot-reload.

Each preset is self-contained: Biome does not apply an extends inside an extended config, so react.json repeats base.json, and a test keeps the two in sync.

The presets leave vcs off: vcs.useIgnoreFile fails outright when the config's folder has no .gitignore. A project that checks its whole tree lists exclusions in files.includes (["**", "!sdks", "!build"]).

A project's files.includes replaces a preset's rather than merging with it, so exclusions live in the project. overrides do merge: a project's own overrides apply alongside the preset's.

Svelte

Svelte apps stay on @anarkisti/eslint-config, since svelte-check holds them at TypeScript 6 either way. Biome 2.5's experimental Svelte support compiled to identical components across the fleet with html.formatter.whitespaceSensitivity: "strict", and needs noUnusedVariables off for *.svelte (it misses variables used only in markup).