collect()

completion이 방출하기 전까지 모든 이벤트를 어레이로 묶어서 리턴함.

let numbers = (0...10)
cancellable = numbers.publisher
    .collect()
    .sink { print("\\($0)") }
//// Prints: "[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10]"

let numbers = (0...10)
cancellable = numbers.publisher
    .collect(5)
    .sink { print("\\($0), terminator: " "") }
// Prints "[0, 1, 2, 3, 4] [5, 6, 7, 8, 9] [10] "
//지정한 개수별로 묶어서 

collect(_ strategy: Pulishers.TimeGroupingStrategy<S>, option: S.SchedulerOptions? = nil)

타이머를 collection 해줌.

let sub = Timer.publish(every: 1, on: .main, in: .default)
    .autoconnect()
    .collect(.byTime(RunLoop.main, .seconds(5)))
    .sink { print("\\($0)", terminator: "\\n\\n") }

// Prints: "[2020-01-24 00:54:46 +0000, 2020-01-24 00:54:47 +0000,
//          2020-01-24 00:54:48 +0000, 2020-01-24 00:54:49 +0000,
//          2020-01-24 00:54:50 +0000]"

ignoreOutout()

• 모든 요소를 무시하고 completion이 fail or finsihed 결과만을 받음.

struct NoZeroValuesAllowedError: Error {}
let numbers = [1, 2, 3, 4, 5, 0, 6, 7, 8, 9]
cancellable = numbers.publisher
    .tryFilter({ anInt in
        guard anInt != 0 else { throw NoZeroValuesAllowedError() }
        return anInt < 20
    })
    .ignoreOutput()
    .sink(receiveCompletion: {print("completion: \\($0)")},
          receiveValue: {print("value \\($0)")})

reduect(initalResult, nextPartialResult) ,tryReduce()

• 기존 리듀스와 방식은 유사함.

let numbers = (0...10)
cancellable = numbers.publisher
    .reduce(0, { accum, next in accum + next })
    .sink { print("\\($0)") }

// Prints: "55"