Scoped

Isolate State Per Request or Page

Scoped lifetime gives each scope its own instance. Use container.extend() to create a child scope when a request, page, conversation, or test needs isolated state while still sharing root singletons.

Creating a Scope With container.extend()

Call root.extend() to create a child container. Services marked LoadAs.Scoped get fresh instances in each child. Singletons from the root are still shared.

request_scope.ts

import createContainer, { Component, Inject, LoadAs } from "@noego/ioc";

@Component({ scope: LoadAs.Scoped })
export class RequestState {
  userId: string | null = null;
}

@Component({ scope: LoadAs.Scoped })
export class CurrentUserWriter {
  constructor(
    @Inject(RequestState) private state: RequestState,
  ) {}

  setUser(userId: string): void {
    this.state.userId = userId;
  }
}

const root = createContainer();
const requestScope = root.extend();
const writer = await requestScope.instance(CurrentUserWriter);

Scope Inheritance

Child containers inherit all registrations from their parent. You can override any registration in a child container without affecting the parent or siblings. This is how test mocks work — register a fake on the test's child container, and the real container tree is untouched.

Rules

Use Scoped for request, page, user, conversation, or test-case state.
Scoped instances are isolated to one child container created via container.extend().
Root singletons remain shared across scopes — they are not re-created.
Pass runtime values to scoped classes via Parameter tokens (see Parameters page).
Dispose scoped containers when the request or page completes to free memory.

Singleton Lifetimes Transient