Forex API daily

Daily European Central Bank web‑scraper that extracts FX rates, computes cross rates, and stores them in Firestore. Exposed as an HTTP Cloud Function (main).

Requirements

• Node.js 22 (see .nvmrc). If your shell selects a different version, run nvm use.
• PNPM as the package manager (recommend corepack enable && corepack install).

Setup

pnpm install

Common Commands

• Build: pnpm compile (TypeScript → index.js).
• Lint/format: pnpm lint, pnpm format (use pnpm lint --fix to auto‑fix).
• Start locally: GCP_PROJECT_ID=forex-api-daily pnpm start (Functions Framework on http://localhost:8081/main).
• Test: pnpm test (runs Vitest; may use Firestore emulator if configured). If you hit PNPM migration issues with lifecycle scripts, run build/lint directly and let us know to update scripts.
• Start Firestore emulator: pnpm start-db (runs on http://localhost:8080).

How It Works

• Fetch: Scrapes ECB RSS endpoints to gather daily EUR base rates.
• Process: Combines latest day’s rates and derives cross rates for other bases.
• Store: Writes documents to the exchange_rates collection; periodically removes stale dates.

CI/CD

• GitHub Actions (.github/workflows/ci.yml) runs tests on push. Deploys from main to Cloud Functions using repo secrets for GCP.

Notes

• Do not commit credentials. Files like .env and service-account.json are ignored by Git.
• The compiled index.js is generated; avoid committing build artifacts.