Functions Typescript Guide

Workflow

1. Identify HTTP verb + resource  →  decide filename: <resource>-<verb>.ts
2. Load structure-http-templates  →  use correct app.http() template
3. Add Cosmos DB / auth if needed →  load database-auth-testing.md
4. Validate with zod              →  parse body as unknown → ZodSchema.parse()
5. Handle all error branches      →  400 / 401 / 403 / 404 / 500
6. Write unit tests               →  createMockRequest + createMockContext
7. Update docs                    →  OpenAPI + README + CHANGELOG
8. Run quality checklist          →  quality-checklist-antipatterns.md

Quick Reference

File naming:   src/functions/<resource>-<verb>.ts
Registration:  app.http('<resource>-<verb>', { methods, authLevel, route, handler })
HTTP client:   fetch()  →  no axios / node-fetch
UUID:          randomUUID()  from node:crypto
File IO:       fs.readFile() from node:fs/promises  (never sync)
Validation:    zod schema → .parse(body)  →  catch ZodError → 400
Auth:          extractBearerToken() → null=401 / validateToken() → false=403
Cosmos init:   module-level (init once, reuse across invocations)
Cosmos 404:    catch error.code === 404 → return null, re-throw others
Error helper:  createErrorResponse(status, error, message?, details?)