Overview

The @cqrs-ddd packages are TypeScript building blocks designed to operate without framework lock-in. They fall into two independent core families (the pipeline and DDD primitives), complemented by two application runtimes: framework-free @cqrs-ddd/cqrs and the official NestJS adapter @cqrs-ddd/nestjs.

The pipeline family

@cqrs-ddd/pipeline is the central execution engine: createPipeline() configures behaviors once, and pipeline.wrap() runs them around a plain function or a class method. A behavior is an object with one method, handle(context, next), allowing it to act before the call, after it, or instead of it.

Each @cqrs-ddd/pipeline-<name> package provides one specialized concern as a behavior:

Concern	Package
Logging	@cqrs-ddd/pipeline (LoggingBehavior, logging())
Validation	@cqrs-ddd/pipeline-zod
Authorization	@cqrs-ddd/pipeline-casl
Caching	@cqrs-ddd/pipeline-cache
Idempotency	@cqrs-ddd/pipeline-idempotency
Rate limits	@cqrs-ddd/pipeline-rate-limit
Retry, timeout, bulkhead	@cqrs-ddd/pipeline-resilience
Feature flags	@cqrs-ddd/pipeline-feature-flags
Audit trail	@cqrs-ddd/pipeline-audit
Dead letters	@cqrs-ddd/pipeline-deadletter
Traces and metrics	@cqrs-ddd/pipeline-opentelemetry
Tenant, correlation id, job context	@cqrs-ddd/pipeline-tenant, @cqrs-ddd/pipeline-correlation, @cqrs-ddd/pipeline-job-context

A behavior is a plain class: its constructor takes whatever dependencies it requires (a cache, a store, a client) without relying on any dependency-injection container. Behaviors mapping errors to HTTP responses export toHttpResponse(error) from a separate /http entry point, usable with any HTTP framework.

The DDD family

@cqrs-ddd/core provides aggregate roots, domain events, command and query base classes, repository contracts, and a revision-fenced repository cache; @cqrs-ddd/mikro-orm adapts its repositories to MikroORM.

@cqrs-ddd/safe-stringify, @cqrs-ddd/untyped, and @cqrs-ddd/uuidv7 are small, zero-dependency utilities shared across both families.

Application runtimes

Depending on your target architecture, two application runtimes run handlers through pipelines:

1. Framework-free CQRS (@cqrs-ddd/cqrs)

@cqrs-ddd/cqrs runs commands, queries, and events without any framework:

• Uses @CommandHandler, @QueryHandler, and @EventsHandler on handler classes.
• Declares behaviors with @UsePipeline and @SkipPipeline from @cqrs-ddd/pipeline.
• createCqrs() instantiates CommandBus, QueryBus, EventBus, and UnhandledExceptionBus.
• No DI container: the application constructs handlers with new and registers them. See CQRS without NestJS. The repository’s api/ is a complete application built this way.

2. NestJS Adapter (@cqrs-ddd/nestjs)

@cqrs-ddd/nestjs glues the packages into an existing NestJS application:

• Keeps official @nestjs/cqrs handlers, buses, and NestJS dependency injection.
• PipelineModule.forRoot() compiles @cqrs-ddd/pipeline behaviors around @nestjs/cqrs handlers at bootstrap.
• ErrorFilter maps all @cqrs-ddd errors to NestJS HttpException instances matching Nest’s standard JSON response body.
• Provides CorrelationMiddleware and JobContextModule for tracing and worker queues. See NestJS & @cqrs-ddd and the @cqrs-ddd/nestjs package guide.

Using them together

Neither the pipeline nor the DDD family depends on the other. A BaseCommand, BaseQuery, or DomainEvent from @cqrs-ddd/core carries the REQUEST_KIND brand symbol that informs pipeline behaviors of its kind, allowing decorated handlers to run without explicit configuration: see DDD without a framework.