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Coding Standards

Lumio uses Biome for linting and formatting in both apps. The frontend also runs ESLint, and its SCSS is checked with stylelint. Follow the conventions of the surrounding code.

Language and formatting​

  • TypeScript everywhere
  • Biome formatting: 2 spaces, single quotes, semicolons, 100-character lines
  • Prefer const (useConst is an error)
  • Avoid any (noExplicitAny warns)
  • Keep functions small and focused

Naming conventions​

  • camelCase for variables and functions
  • PascalCase for classes, types, and React component files (for example AppChrome.tsx)
  • kebab-case for other files (for example password-reset.service.ts)
  • UPPER_SNAKE_CASE for constants

Biome does not enforce naming (useNamingConvention is off), so match the files next to yours.

Lint and format​

npm --prefix backend run lint:check
npm --prefix frontend run lint:check   # Biome + ESLint
npm --prefix backend run lint:fix
npm --prefix frontend run lint:fix
make format

On the frontend, fixing only Biome or only ESLint leaves CI red.

Backend rules​

  • Every tenant-owned query filters by workspaceId
  • Keep controllers thin: logic in services, input validation in DTOs
  • Schema changes only through migrations

Code review expectations​

  • Ensure tests cover new behavior
  • Document any breaking changes
  • Add migration notes for schema updates

Next: Adding a Bank Parser