A publisher that applies an error-throwing closure to all received elements and produces an accumulated value when the upstream publisher finishes.
SDKs
Framework
struct TryReduce<Upstream, Output> where Upstream : Publisher
let initial: OutputThe initial value provided on the first invocation of the closure.
let nextAn error-throwing closure that takes the previously-accumulated value and the next element from the upstream to produce a new value.
let upstream: UpstreamThe publisher from which this publisher receives elements.
func allPublishes a single Boolean value that indicates whether all received elements pass a given predicate.
func append(Output...) -> PublishersAppend the output of a publisher with the specified sequence.
func assertRaises a fatal error when its upstream publisher fails, and otherwise republishes all received input.
func breakpoint(receiveRaises a debugger signal when a provided closure needs to stop the process in the debugger.
func breakpointRaises a debugger signal upon receiving a failure.
func buffer(size: Int, prefetch: PublishersBuffers elements received from an upstream publisher.
func `catch`<P>((Error) -> P) -> PublishersHandles errors from an upstream publisher by replacing it with another publisher.
func collect() -> PublishersCollects all received elements, and emits a single array of the collection when the upstream publisher finishes.
func collect(Int) -> PublishersCollects up to the specified number of elements, and then emits a single array of the collection.
func collect<S>(PublishersCollects elements by a given strategy, and emits a single array of the collection.
func combineSubscribes to an additional publisher and publishes a tuple upon receiving output from either publisher.
func combineSubscribes to two additional publishers and publishes a tuple upon receiving output from any of the publishers.
func combineSubscribes to an additional publisher and invokes a closure upon receiving output from either publisher.
func combineSubscribes to three additional publishers and publishes a tuple upon receiving output from any of the publishers.
func combineSubscribes to two additional publishers and invokes a closure upon receiving output from any of the publishers.
func combineSubscribes to three additional publishers and invokes a closure upon receiving output from any of the publishers.
func compactCalls a closure with each received element and publishes any returned optional that has a value.
func contains(Output) -> PublishersPublishes a Boolean value upon receiving an element equal to the argument.
func contains(where: (Output) -> Bool) -> PublishersPublishes a Boolean value upon receiving an element that satisfies the predicate closure.
func count() -> PublishersPublishes the number of elements received from the upstream publisher.
func debounce<S>(for: SPublishes elements only after a specified time interval elapses between events.
func decode<Item, Coder>(type: ItemDecodes the output from upstream using a specified decoder.
func delay<S>(for: SDelays delivery of all output to the downstream receiver by a specified amount of time on a particular scheduler.
func drop<P>(untilIgnores elements from the upstream publisher until it receives an element from a second publisher.
func drop(while: (Output) -> Bool) -> PublishersOmits elements from the upstream publisher until a given closure returns false, before republishing all remaining elements.
func dropOmits the specified number of elements before republishing subsequent elements.
func encode<Coder>(encoder: Coder) -> PublishersEncodes the output from upstream using a specified encoder.
func eraseWraps this publisher with a type eraser.
func filter((Output) -> Bool) -> PublishersRepublishes all elements that match a provided closure.
func first() -> PublishersPublishes the first element of a stream, then finishes.
func first(where: (Output) -> Bool) -> PublishersPublishes the first element of a stream to satisfy a predicate closure, then finishes.
func flatTransforms all elements from an upstream publisher into a new or existing publisher.
func handlePerforms the specified closures when publisher events occur.
func ignoreIngores all upstream elements, but passes along a completion state (finished or failed).
func last() -> PublishersPublishes only the last element of a stream, after the stream finishes.
func last(where: (Output) -> Bool) -> PublishersPublishes only the last element of a stream that satisfies a predicate closure, after the stream finishes.
func map<T>((Output) -> T) -> PublishersTransforms all elements from the upstream publisher with a provided closure.
func map<T>(KeyPublishes the value of a key path.
func map<T0, T1>(KeyPublishes the values of two key paths as a tuple.
func map<T0, T1, T2>(KeyPublishes the values of three key paths as a tuple.
func mapConverts any failure from the upstream publisher into a new error.
func max() -> PublishersPublishes the maximum value received from the upstream publisher, after it finishes.
func max(by: (Output, Output) -> Bool) -> PublishersPublishes the maximum value received from the upstream publisher, using the provided ordering closure.
func measureMeasures and emits the time interval between events received from an upstream publisher.
func merge(with: PublishersCombines elements from this publisher with those from another publisher of the same type, delivering an interleaved sequence of elements.
func merge<B, C>(with: B, C) -> PublishersCombines elements from this publisher with those from two other publishers, delivering an interleaved sequence of elements.
func merge<B, C, D>(with: B, C, D) -> PublishersCombines elements from this publisher with those from three other publishers, delivering an interleaved sequence of elements.
func merge<B, C, D, E>(with: B, C, D, E) -> PublishersCombines elements from this publisher with those from four other publishers, delivering an interleaved sequence of elements.
func merge<B, C, D, E, F>(with: B, C, D, E, F) -> PublishersCombines elements from this publisher with those from five other publishers, delivering an interleaved sequence of elements.
func merge<B, C, D, E, F, G>(with: B, C, D, E, F, G) -> PublishersCombines elements from this publisher with those from six other publishers, delivering an interleaved sequence of elements.
func merge<B, C, D, E, F, G, H>(with: B, C, D, E, F, G, H) -> PublishersCombines elements from this publisher with those from seven other publishers, delivering an interleaved sequence of elements.
func min() -> PublishersPublishes the minimum value received from the upstream publisher, after it finishes.
func min(by: (Output, Output) -> Bool) -> PublishersPublishes the minimum value received from the upstream publisher, after it finishes.
func multicast<S>(() -> S) -> PublishersApplies a closure to create a subject that delivers elements to subscribers.
func multicast<S>(subject: S) -> PublishersProvides a subject to deliver elements to multiple subscribers.
func output(at: Int) -> PublishersPublishes a specific element, indicated by its index in the sequence of published elements.
func output<R>(in: R) -> PublishersPublishes elements specified by their range in the sequence of published elements.
func prefix(Int) -> PublishersRepublishes elements up to the specified maximum count.
func prefix<P>(untilRepublishes elements until another publisher emits an element.
func prefix(while: (Output) -> Bool) -> PublishersRepublishes elements while a predicate closure indicates publishing should continue.
func prepend(Output...) -> PublishersPrefixes the output of a publisher with the specified sequence.
func print(String, to: TextPrints log messages for all publishing events.
func receive<S>(on: S, options: SSpecifies the scheduler on which to receive elements from the publisher.
func reduce<T>(T, (T, Output) -> T) -> PublishersApplies a closure that accumulates each element of a stream and publishes a final result upon completion.
func removePublishes only elements that don’t match the previous element.
func removePublishes only elements that don’t match the previous element, as evaluated by a provided closure.
func replaceReplaces an empty stream with the provided element.
func replaceReplaces any errors in the stream with the provided element.
func replaceReplaces nil elements in the stream with the provided element.
func retry(Int) -> PublishersAttempts to recreate a failed subscription with the upstream publisher using a specified number of attempts to establish the connection.
func scan<T>(T, (T, Output) -> T) -> PublishersTransforms elements from the upstream publisher by providing the current element to a closure along with the last value returned by the closure.
func share() -> PublishersReturns a publisher as a class instance.
func sink(receiveAttaches a subscriber with closure-based behavior.
func subscribe<S>(S) -> AnyAttaches the specified subject to this publisher.
func subscribe<S>(S)Attaches the specified subscriber to this publisher.
func subscribe<S>(on: S, options: SSpecifies the scheduler on which to perform subscribe, cancel, and request operations.
func switchFlattens the stream of events from multiple upstream publishers to appear as if they were coming from a single stream of events.
func throttle<S>(for: SPublishes either the most-recent or first element published by the upstream publisher in the specified time interval.
func timeout<S>(STerminates publishing if the upstream publisher exceeds the specified time interval without producing an element.
func tryPublishes a single Boolean value that indicates whether all received elements pass a given error-throwing predicate.
func tryHandles errors from an upstream publisher by replacing it with another publisher or an error.
func tryCalls an error-throwing closure with each received element and publishes any returned optional that has a value.
func tryPublishes a Boolean value upon receiving an element that satisfies the throwing predicate closure.
func tryOmits elements from the upstream publisher until an error-throwing closure returns false, before republishing all remaining elements.
func tryRepublishes all elements that match a provided error-throwing closure.
func tryPublishes the first element of a stream to satisfy a throwing predicate closure, then finishes.
func tryPublishes only the last element of a stream that satisfies an error-throwing predicate closure, after the stream finishes.
func tryTransforms all elements from the upstream publisher with a provided error-throwing closure.
func tryPublishes the maximum value received from the upstream publisher, using the provided error-throwing closure to order the items.
func tryPublishes the minimum value received from the upstream publisher, using the provided error-throwing closure to order the items.
func tryRepublishes elements while a error-throwing predicate closure indicates publishing should continue.
func tryApplies an error-throwing closure that accumulates each element of a stream and publishes a final result upon completion.
func tryPublishes only elements that don’t match the previous element, as evaluated by a provided error-throwing closure.
func tryTransforms elements from the upstream publisher by providing the current element to an error-throwing closure along with the last value returned by the closure.
func zip<P>(P) -> PublishersCombines elements from another publisher and deliver pairs of elements as tuples.
func zip<P, Q>(P, Q) -> PublishersCombines elements from two other publishers and delivers groups of elements as tuples.
func zip<P, T>(P, (Output, PCombines elements from another publisher and delivers a transformed output.
func zip<P, Q, R>(P, Q, R) -> PublishersCombines elements from three other publishers and delivers groups of elements as tuples.
func zip<P, Q, T>(P, Q, (Output, PCombines elements from two other publishers and delivers a transformed output.
func zip<P, Q, R, T>(P, Q, R, (Output, PCombines elements from three other publishers and delivers a transformed output.
struct PublishersA publisher that buffers items.
struct PublishersA publisher that buffers a maximum number of items.
struct PublishersA publisher that buffers and periodically publishes its items.
enum PublishersA strategy for collecting received elements.
struct PublishersA publisher that ignores all upstream elements, but passes along a completion state (finish or failed).
struct PublishersA publisher that applies a closure to all received elements and produces an accumulated value when the upstream publisher finishes.