ControlNotificationStream.first(where:)

Description#

In this example, an asynchronous sequence called Counter produces Int values from 1 to 10. The first(where:) method returns the first member of the sequence that's evenly divisible by both 2 and 3.

let divisibleBy2And3 = await Counter(howHigh: 10) .first { $0 % 2 == 0 && $0 % 3 == 0 } print(divisibleBy2And3 ?? "none") // Prints "6"

The predicate executes each time the asynchronous sequence produces an element, until either the predicate finds a match or the sequence ends.

• Parameter predicate: A closure that takes an element of the asynchronous sequence as its argument and returns a Boolean value that indicates whether the element is a match.
• Returns: The first element of the sequence that satisfies predicate, or nil if there is no element that satisfies predicate.