@nestarc/feature-flag

DB-backed feature flags for NestJS + Prisma + PostgreSQL -- tenant-aware overrides, percentage rollouts, and zero external dependencies.

Features

Database-backed -- flags stored in PostgreSQL via Prisma, no external service required
Tenant / user / environment overrides -- granular control per tenant, user, or deployment environment
Percentage rollouts -- deterministic hashing (murmurhash3) for consistent per-user bucketing
Guard decorator -- @FeatureFlag() automatically gates routes and controllers
Bypass decorator -- @BypassFeatureFlag() exempts health checks and public endpoints
Programmatic evaluation -- isEnabled(), evaluateAll(), and findByKey() for service-layer logic
Pluggable cache -- CacheAdapter interface with built-in MemoryCacheAdapter (default) and RedisCacheAdapter v0.2.0
Redis Pub/Sub -- cross-instance cache invalidation for horizontal scaling v0.2.0
Admin REST API -- opt-in FeatureFlagAdminModule with mandatory guard injection v0.2.0
Repository pattern -- FeatureFlagRepository interface for custom persistence backends v0.2.0
Tenant context provider -- automatic @nestarc/tenancy integration via TenantContextProvider v0.2.0
Event system -- optional integration with @nestjs/event-emitter for audit and observability
Testing utilities -- drop-in TestFeatureFlagModule for unit and integration tests

bash

npm install @nestarc/feature-flag

bash

npm install @nestjs/common @nestjs/core @prisma/client rxjs reflect-metadata

bash

# Required only if you enable emitEvents
npm install @nestjs/event-emitter

# Required only if you use RedisCacheAdapter
npm install ioredis