# allSatisfy(_:) Publishes a single Boolean value that indicates whether all received elements pass a given predicate. ``` func allSatisfy(_ predicate: @escaping (Self.Output) -> Bool) -> Publishers.AllSatisfy ``` ## Parameters `predicate` A closure that evaluates each received element. Return `true` to continue, or `false` to cancel the upstream and complete. ## Return Value A publisher that publishes a Boolean value that indicates whether all received elements pass a given predicate. ## Discussion Use the [`allSatisfy(_:)`](/documentation/Combine/Publisher/allSatisfy(_:)) operator to determine if all elements in a stream satisfy a criteria you provide. When this publisher receives an element, it runs the predicate against the element. If the predicate returns `false`, the publisher produces a `false` value and finishes. If the upstream publisher finishes normally, this publisher produces a `true` value and finishes. In the example below, the [`allSatisfy(_:)`](/documentation/Combine/Publisher/allSatisfy(_:)) operator tests if each an integer array publisher’s elements fall into the `targetRange`: ``` let targetRange = (-1...100) let numbers = [-1, 0, 10, 5] numbers.publisher .allSatisfy { targetRange.contains($0) } .sink { print("\($0)") } // Prints: "true" ``` With operators similar to [`reduce(_:_:)`](/documentation/Combine/Publisher/reduce(_:_:)), this publisher produces at most one value. > Note: Upon receiving any request greater than zero, this publisher requests unlimited elements from the upstream 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)