publisher

Declaration

var publisher: Result<Success, Failure>.Publisher { get }

Discussion

In the following example, goodResult provides a successful result with the integer value 1. A sink subscriber connected to the result’s publisher receives the output 1, followed by a normal completion (Subscribers.Completion.finished).

 let goodResult: Result<Int, MyError> = .success(1)
 goodResult.publisher
     .sink(receiveCompletion: { print("goodResult done: \($0)")},
           receiveValue: { print("goodResult value: \($0)")} )
 // Prints:
 // goodResult value: 1
 // goodResult done: finished

In contrast with the Just publisher, which always publishes a single value, this publisher might not send any values and instead terminate with an error, if the result is /Swift/Result/failure. In the next example, badResult is a failure result that wraps a custom error. A sink subscriber connected to this result’s publisher immediately receives a termination (Subscribers.Completion.failure(_:)).

 struct MyError: Error, CustomDebugStringConvertible {
     var debugDescription: String = "MyError"
 }
 let badResult: Result<Int, MyError> = .failure(MyError())
 badResult.publisher
     .sink(receiveCompletion: { print("badResult done: \($0)")},
           receiveValue: { print("badResult value: \($0)")} )
 // Prints:
 // badResult done: failure(MyError)

See Also

Publishing a Result

• Result.Publisher