Scoped dependencies

Scoped dependencies cache one value for each context key. Compdi provides an accessor form and a contextual proxy form.

Keyed accessor

defineScoped returns a callable accessor. Supply the context key when resolving a value:

const useRequestService = defineScoped<RequestService, Request>({
  target: RequestService,
  deps: [database],
  onRelease: service => service.close(),
});

const service = useRequestService(request);

useRequestService.has(request);     // true
useRequestService.peek(request);    // existing value, without creating one
await useRequestService.release(request);

The lifecycle methods never create a value:

• has(context) reports whether an entry exists.
• peek(context) returns an existing entry or undefined.
• release(context) removes the entry and runs onRelease, when configured.

Contextual proxy

createScoped returns a stable proxy and a controller. The proxy asks context() for the active key when one of its properties is used:

const [database, databaseScope] = createScoped({
  factory: request => createRequestDatabase(request),
  context: useRequest,
  onRelease: instance => instance.close(),
});

database.query("SELECT 1");
await databaseScope.release(request);

Use the proxy form when an ambient context is already available. Use the accessor form when passing the context explicitly makes ownership clearer.