How does moduleRef.resolve() work with scoped providers and what is ContextIdFactory used for?

Q: How does moduleRef.resolve() work with scoped providers and what is ContextIdFactory used for?

@Injectable() export class DynamicFactory { constructor(private moduleRef: ModuleRef) {} async getIsolated() { // Each resolve() creates a fresh independent context const svcA = await this.moduleRef.resolve(RequestScopedService); const svcB = await this.moduleRef.resolve(RequestScopedService); // svcA !== svcB — different instances } async getShared() { // ContextIdFactory.create() ties multiple resolves to one context const ctxId = ContextIdFactory.create(); const svcA = await this.moduleRef.resolve(ServiceA, ctxId); const svcB = await this.moduleRef.resolve(ServiceB, ctxId); // ServiceA and ServiceB share the same DI context // If ServiceB depends on the same REQUEST-scoped provider as ServiceA, // they get the same instance } } moduleRef.get() — synchronous, returns existing singleton, cannot resolve scoped providers. moduleRef.resolve() — asynchronous, creates a new DI sub-context for scoped providers. Each resolve() without a contextId creates a completely isolated context — fresh transient instances. Pass the same contextId to multiple resolve() calls to share one scoped context across providers.

Difficulty: 6/10

Scoped providers, ModuleRef.resolve, ContextIdFactory

moduleRef.resolve() creates a new DI sub-context and instantiates the provider within it — required for REQUEST and TRANSIENT scoped providers. ContextIdFactory.create() generates a reusable context ID so that multiple resolve() calls can share the same scoped context and receive the same instance.

resolve() and ContextIdFactory usage

Summary of differences:

1
moduleRef.get() — synchronous, returns existing singleton, cannot resolve scoped providers.
2
moduleRef.resolve() — asynchronous, creates a new DI sub-context for scoped providers.

How does moduleRef.resolve() work with scoped providers and what is ContextIdFactory used for?

Difficulty: 6/10

Scoped providers, ModuleRef.resolve, ContextIdFactory

moduleRef.resolve() creates a new DI sub-context and instantiates the provider within it — required for REQUEST and TRANSIENT scoped providers. ContextIdFactory.create() generates a reusable context ID so that multiple resolve() calls can share the same scoped context and receive the same instance.

resolve() and ContextIdFactory usage

Summary of differences:

1
moduleRef.get() — synchronous, returns existing singleton, cannot resolve scoped providers.
2
moduleRef.resolve() — asynchronous, creates a new DI sub-context for scoped providers.

How does moduleRef.resolve() work with scoped providers and what is ContextIdFactory used for?

How does moduleRef.resolve() work with scoped providers and what is ContextIdFactory used for?

Scenario Questions

Follow-up Questions