Scaffolding for Publisher.prefixInclusive’s two cases.

prefix_while_inclusive_case_scaffolding.swift

extension Publisher {
	func prefixInclusive(while predicate: @escaping (Output) -> Bool) -> AnyPublisher<Output, Failure> {
		flatMap { value -> AnyPublisher<PrefixInclusiveEvent<Output>, Failure> in
			if predicate(value) {
				return Just(.predicatePassingValueOrIncluded(value))
					.setFailureType(to: Failure.self)
					.eraseToAnyPublisher()
			} else {
				return [.predicatePassingValueOrIncluded(value), .end]
					.publisher // (1) `Sequence.publisher` is a hidden gem for converting an ordinary sequence
					// into a publisher of elements, followed by a completion when the underlying iterator `nil`s out.
					.setFailureType(to: Failure.self) // (2) We’ll tidy up the `setFailureType`-`eraseToAnyPublisher` dance
					// we have to do in each clause.
					.eraseToAnyPublisher()
			}
		}
		.eraseToAnyPublisher() // ❌ “Type of expression is ambiguous without more context.”
	}
}