express-api

fireclass-js — Express example

A complete CRUD API for a users collection, built with @dharayush7/fireclass-js. It demonstrates the model definition, typed queries, validation, and the Express error handler.

Files

• src/firebase.ts — memoized firebase-admin init (emulator-aware)
• src/models/user.ts — the User model with class-validator decorators
• src/server.ts — Express routes + fireclassErrorHandler()

Run it against the Firestore emulator

# 1. Install
pnpm install

# 2. Start the Firestore emulator (needs the Firebase CLI + Java)
firebase emulators:start --only firestore

# 3. In another terminal, point the app at the emulator and start it
export FIRESTORE_EMULATOR_HOST=localhost:8080
export GCLOUD_PROJECT=fireclass-demo
pnpm dev

Try the API

# Create (validated) — 201
curl -X POST localhost:3000/users -H 'content-type: application/json' \
  -d '{"name":"Ada Lovelace","email":"ada@example.com","age":36}'

# Create invalid — 400 with field-level details
curl -X POST localhost:3000/users -H 'content-type: application/json' \
  -d '{"name":"A","email":"nope","age":-1}'

# List (optionally filter): GET /users?minAge=18
curl localhost:3000/users
curl 'localhost:3000/users?minAge=30'

# Read / update / delete
curl localhost:3000/users/<id>
curl -X PATCH localhost:3000/users/<id> -H 'content-type: application/json' -d '{"age":37}'
curl -X DELETE localhost:3000/users/<id>

Against a real project

Two options, both handled by src/firebase.ts:

1. Drop a key in this folder. Download a service-account key from Firebase Console → Project Settings → Service accounts → Generate new private key and save it here as serviceAccount.json. It is gitignored (serviceAccount*.json) — never commit it. Then:

   pnpm start   # auto-detects ./serviceAccount.json

2. Use ADC. Set GOOGLE_APPLICATION_CREDENTIALS=/path/to/key.json (and optionally GCLOUD_PROJECT=your-project-id), then pnpm start.

The database must exist: Firebase Console → Build → Firestore Database → Create database. Otherwise you'll get PERMISSION_DENIED: Cloud Firestore API has not been used….

A note on queries + indexes

GET /users?minAge=30 filters by age and therefore orders by age — because Firestore requires the field in a range filter (>=, <, …) to be the first orderBy. Ordering by a different field than the range filter (e.g. filter age but order by name) needs a composite index, which Firestore will prompt you to create via a console link in the error. See src/server.ts for how the example picks the order field.