pedwfrontend/context/coding-conventions.md

Coding Conventions (Repository-Specific)

Language and Style

• Default to JavaScript for new work unless area is already TypeScript.
• Use existing formatting:
  • 4 spaces
  • no trailing commas
  • preserve existing quote style in touched file
• Avoid broad stylistic rewrites in functional changes.

File Placement and Boundaries

• Keep pages/ focused on route wiring, data fetch orchestration, and composition.
• Move reusable domain logic into lib/ or actions/.
• Keep reusable UI in components/ (feature subfolders preferred).
• Keep Redux behavior changes localized to relevant slice and store/store.js integration points.

API Route Conventions

• Follow existing API naming where present (*_api.js in pages/api/endpoint, pages/api/file, pages/api/admin).
• Maintain explicit error handling and return predictable response shapes.
• For sensitive endpoints, include authorization and invalid-input paths.

Auth/Session Conventions

• pages/api/auth/[...nextauth].js is authoritative for auth flow behavior.
• Do not bypass session checks in protected routes/components.
• Preserve secure redirect/callback behavior and cookie safety settings.

i18n Conventions

• Add user-facing strings to locale files (locales/en, locales/cy) where feasible.
• Keep EN/CY route behavior aligned when adding/changing pages.
• If a route alias changes in Welsh, verify rewrite mapping in next.config.js and page namespaces in i18n.js.

Accessibility Conventions

• Use semantic HTML and maintain heading hierarchy.
• Ensure keyboard access and visible focus states.
• Provide meaningful labels and error messages.

Logging and Error Handling

• Never log secrets, tokens, personal details, or raw credential payloads.
• Keep operational logs concise and safe for production telemetry.
• Prefer structured, actionable errors over generic catch-and-ignore patterns.

Legacy and Mixed-Pattern Guidance

• Where conventions conflict between folders, follow the dominant local pattern and record exceptions in memory-bank/decisions.md.
• Refactor incrementally: separate behavior changes from structural cleanup.