# eraseToAnyPublisher() Wraps this publisher with a type eraser. ``` func eraseToAnyPublisher() -> AnyPublisher ``` ## Return Value An [`AnyPublisher`](/documentation/Combine/AnyPublisher) wrapping this publisher. ## Discussion Use [`eraseToAnyPublisher()`](/documentation/Combine/Publisher/eraseToAnyPublisher()) to expose an instance of [`AnyPublisher`](/documentation/Combine/AnyPublisher) to the downstream subscriber, rather than this publisher’s actual type. This form of *type erasure* preserves abstraction across API boundaries, such as different modules. When you expose your publishers as the [`AnyPublisher`](/documentation/Combine/AnyPublisher) type, you can change the underlying implementation over time without affecting existing clients. The following example shows two types that each have a `publisher` property. `TypeWithSubject` exposes this property as its actual type, [`PassthroughSubject`](/documentation/Combine/PassthroughSubject), while `TypeWithErasedSubject` uses [`eraseToAnyPublisher()`](/documentation/Combine/Publisher/eraseToAnyPublisher()) to expose it as an [`AnyPublisher`](/documentation/Combine/AnyPublisher). As seen in the output, a caller from another module can access `TypeWithSubject.publisher` as its native type. This means you can’t change your publisher to a different type without breaking the caller. By comparison, `TypeWithErasedSubject.publisher` appears to callers as an [`AnyPublisher`](/documentation/Combine/AnyPublisher), so you can change the underlying publisher type at will. ``` public class TypeWithSubject { public let publisher: some Publisher = PassthroughSubject() } public class TypeWithErasedSubject { public let publisher: some Publisher = PassthroughSubject() .eraseToAnyPublisher() } // In another module: let nonErased = TypeWithSubject() if let subject = nonErased.publisher as? PassthroughSubject { print("Successfully cast nonErased.publisher.") } let erased = TypeWithErasedSubject() if let subject = erased.publisher as? PassthroughSubject { print("Successfully cast erased.publisher.") } // Prints "Successfully cast nonErased.publisher." ``` --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)