Swift Concurrency & Combine.

Structured concurrency (async/await, actors) and Combine reactive streams — the headline senior-iOS axis. Covers 2 sub-skills.

• Swift Concurrency & Combine · 1 of 3

  Combine Framework & Reactive Streams

  In Combine, what type does the operator chain Just(5).map { $0 + 1 } ultimately conform to?

  AA Subscriber that pulls Int values from its upstream chainBA Publisher whose Output is Int and whose Failure is NeverCA Subject you can feed new Int values into using sendDA Cancellable token you must retain to keep the stream alive

• Swift Concurrency & Combine · 2 of 3

  Combine Framework & Reactive Streams

  A teammate iterates a CurrentValueSubject through its async-sequence bridge with for-await. What does the loop see before any further send() calls?

  Athe latest stored element, then any future emissionsBthe most recent element if it changed within one frameConly elements published strictly after iteration startsDnothing until completion, then the final stored element

• Swift Concurrency & Combine · 3 of 3

  Swift Concurrency (async/await & Actors)

  What does this snippet print before catch swallows the error?

  struct E: Error {}let s = AsyncThrowingStream<Int, Error> { c in    c.yield(1); c.finish(throwing: E())}do { for try await v in s { print(v) } } catch { }

  A1BEC3D0