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Code Quality Standards

This project uses Biome for code formatting, linting, and import organization to ensure consistent code quality across the codebase.

Biome Configuration​

Biome has replaced ESLint and Prettier in this project for better performance and a unified tooling experience. The configuration is defined in biome.json at the project root.

Key Settings​

  • Semicolons: Always required ("always")
  • Indentation: 4 spaces
  • Quote Style: Double quotes preferred
  • Line Width: 80 characters
  • Parameter Decorators: Enabled for NestJS compatibility (unsafeParameterDecoratorsEnabled: true)

Available Commands​

# Format all files
pnpm run format

# Check formatting without making changes
pnpm run format:check

# Run linting checks
pnpm run lint

# Fix linting issues automatically
pnpm run lint:fix

IDE Setup​

  1. Install the Biome extension:

    Extension ID: biomejs.biome

  2. Workspace settings are pre-configured in .vscode/settings.json:

    • Format on save enabled
    • Biome set as default formatter
    • Auto-organize imports on save
    • Quick fixes applied automatically

Other Editors​

For other editors, refer to the Biome Editor Integration guide.

File Coverage​

Biome processes the following file types:

  • TypeScript files: src/**/*.ts, test/**/*.ts, src/**/*.spec.ts
  • JavaScript files: *.js, *.mjs
  • JSON files: *.json, *.jsonc

Git Hooks​

The repository uses Husky hooks to run checks locally:

  • pre-commit formats and lints the workspace.
  • pre-push runs pnpm run knip to detect unused files, dependencies, and exports before a push.

Install dependencies with pnpm install to enable the hooks. You can run the checks manually as well:

pnpm -r run format
pnpm -r run lint
pnpm run knip

Code Style Guidelines​

TypeScript/JavaScript​

  • Use explicit types where beneficial for readability
  • Prefer const over let when variables don't change
  • Use meaningful variable and function names
  • Add JSDoc comments for public APIs
  • Destructure objects when accessing multiple properties

NestJS Specific​

  • Use parameter decorators (e.g., @Body(), @Param())
  • Organize imports: external packages, then internal modules
  • Use dependency injection consistently
  • Follow NestJS naming conventions for controllers, services, modules

Example​

import { Injectable } from '@nestjs/common';
import { ConfigService } from '@nestjs/config';

/**
 * Service for managing user authentication.
 */
@Injectable()
export class AuthService {
    constructor(private readonly configService: ConfigService) {}

    /**
     * Validates user credentials.
     * @param email User's email address
     * @param password User's password
     * @returns Authentication result
     */
    async validateUser(email: string, password: string): Promise<boolean> {
        const isValid = await this.checkCredentials(email, password);
        return isValid;
    }
}