linting-formatting

name	linting-formatting
description	Linting and formatting (ESLint, Biome, auto-fix)

Linting and Formatting

Tool docs: ESLint · Biome Configs: ../../../nx.json (targets: eslint, biome) · ../../../biome.json

Running Checks

# Full lint + format check (both ESLint and Biome)
nx run <project>:check

# All projects
nx run-many -t check

# Only lint a single project
nx run <project>:check:eslint --excludeTaskDependencies

# Format only (Biome)
nx run <project>:check:biome --excludeTaskDependencies

Auto-fixing

# Fix lint and format issues
nx run <project>:check --configuration=fix

# Fix all projects
nx run-many -t check -c fix

# Fix only lint for a single project
nx run <project>:check:eslint -c fix --excludeTaskDependencies

# Fix only format for a single project
nx run <project>:check:biome -c fix --excludeTaskDependencies

ESLint

Every package has an eslint.config.js that extends the shared workspace config:

// eslint.config.js (in each package)
import configGenerator from '@leyman/eslint-config';
import packageJson from './package.json' with { type: 'json' };
export default configGenerator({ configUrl: import.meta.url, packageJson });

The @leyman/eslint-config package dynamically generates rules based on the package's package.json. It enables many plugins including:

• @typescript-eslint — TypeScript-specific rules
• eslint-plugin-unicorn — best practices
• eslint-plugin-sonarjs — code quality
• eslint-plugin-import — import ordering and correctness
• eslint-plugin-n — Node.js-specific rules

This config can be extended (via Eslint's Flat Config) but that is unusual. If a rule really needs to be tweaked, it is usually best to fix it for all packages at once in the main config.

Biome

Biome handles formatting only (linting is disabled in biome.json - ESLint handles all linting).

Key formatting rules (biome.json):

• Line width: 100 characters
• Indent: 4 spaces
• Quotes: single for JS/TS, double for JSX
• Semicolons: always
• Trailing commas: ES5 style
• JSON: 2-space indent, one item per line

Biome is not cached in Nx (runs every time). It is fast enough that caching isn't needed.

What Each Tool Covers

Tool	Scope
ESLint	TypeScript logic, imports, code quality
Biome	Formatting (whitespace, quotes, commas, line length) for .ts, .js, .json

CI Behavior

Linting and formatting are required for passing CI.

Fixing Specific Issues

ESLint rule violation — Read the rule documentation linked in the error, or run with --configuration=fix if the rule is auto-fixable.

Eslint rules generally are adopted liberally (often using all rules avaiable) and then disabling/tweaking the ones that don't make sense. Rules may be updated in the main config if the goals do not align with this repo's best practices.

Biome formatting — Always auto-fixable, so long as the code is valid: nx run <project>:biome --configuration=fix.