Lifetimes

InferDI has three lifetimes:

Lifetime	Created	Cached on	Disposed by container
singleton	once per owning container	owner container	yes
scoped	once per child scope	child scope	yes
transient	every resolve	never	no

Resolve scoped keys from a child returned by createScope(). The default checked contract rejects attempts to resolve them from the root container.

The Lifetime Rule

A singleton cannot directly depend on a scoped or transient service. A singleton is created once and shared across every request, so if it captures a scoped value — the current request's context, user, or transaction — that one request's state silently bleeds into all the others. InferDI makes that edge unrepresentable in the type system instead of leaving it to code review.

import { Container } from '@inferdi/inferdi'

class RequestContext {
  readonly requestId = 'req-1'
}

class UserService {
  constructor(readonly request: RequestContext) {}
}

new Container()
  .registerClass('request', RequestContext, [], 'scoped')
  .registerClass('users', UserService, ['request'], 'singleton') 

TypeScript rejects that registration in every runtime contract. The default checked contract also rejects the same shape at runtime if a cast bypasses the type system.

Declared scope inputs count as scoped dependencies. Register a consumer that reads a request, auth context, tenant, or job payload as scoped or transient; the compiler rejects a singleton consumer before runtime. See Scope Inputs.

Runtime enforcement is controlled by the container contract. See Container Options for the exact behavior of the default and fast contracts.