Interface ExistingProvider<T>

Provider that creates an alias to an existing token

When the provide token is resolved, the container resolves useExisting instead. Both tokens return the same instance (for singleton/request-scoped services).

Use cases:

Creating interface tokens that alias concrete implementations
Multiple tokens resolving to the same service

Example: Basic alias

{
  provide: 'IUserService',
  useExisting: UserService
}
// Resolving 'IUserService' returns the UserService instance

Example: Interface abstraction

providers: [
  UserService,
  { provide: I_USER_SERVICE, useExisting: UserService }
]
// Both UserService and I_USER_SERVICE resolve to the same instance

interface ExistingProvider<T extends object = object> {
provide: InjectionToken<T>;
useExisting: InjectionToken<T>;
}

Type Parameters

T extends object = object

Index

Properties

provide useExisting

Properties

provide

provide: InjectionToken<T>

useExisting

useExisting: InjectionToken<T>

Interface ExistingProvider<T>

Example: Basic alias

Example: Interface abstraction

Type Parameters

Index

Properties

Properties

provide

useExisting

Settings

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