# next(isolation:) Produces the next element in the drop-while sequence. ``` mutating func next(isolation actor: isolated (any Actor)?) async throws -> Base.Element? ``` ## Discussion This iterator calls `next(isolation:)` on its base iterator and evaluates the result with the `predicate` closure. As long as the predicate returns `true`, this method returns `nil`. After the predicate returns `false`, for a value received from the base iterator, this method returns that value. After that, the iterator returns values received from its base iterator as-is, and never executes the predicate closure again. If calling the closure throws an error, the sequence ends and `next(isolation:)` rethrows the error. --- 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)