# Publishers.PrefixWhile A publisher that republishes elements while a predicate closure indicates publishing should continue. ``` struct PrefixWhile where Upstream : Publisher ``` ## Topics ### Creating a prefix while publisher [`init(upstream:predicate:)`](/documentation/Combine/Publishers/PrefixWhile/init(upstream:predicate:)) Creates a publisher that republishes elements while a predicate closure indicates publishing should continue. ### Declaring supporting types [`Publishers.PrefixWhile.Output`](/documentation/Combine/Publishers/PrefixWhile/Output) The kind of values published by this publisher. [`Publishers.PrefixWhile.Failure`](/documentation/Combine/Publishers/PrefixWhile/Failure) The kind of errors this publisher might publish. ### Inspecting publisher properties [`upstream`](/documentation/Combine/Publishers/PrefixWhile/upstream) The publisher from which this publisher receives elements. [`predicate`](/documentation/Combine/Publishers/PrefixWhile/predicate) The closure that determines whether publishing should continue. --- 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)