Swift Combine Operator Example, ズンドコキヨシ with Combine

zundoko.swift

import Foundation
import Combine
let ずんどこ水源 = Timer.publish(every: 0.1, on: .main, in: .default)
  .autoconnect()
  .map { _ in Int.random(in:0..<2) == 0 ? "ずん" : "どこ" }
  .share()

let センサー付き水門 = ずんどこ水源
 .scan([], { (reservoir: [String], element: String) -> [String] in
     // 溜池
     var newReservoir = Array(reservoir + [element])
     if newReservoir.count > 5 {
         newReservoir.removeFirst()
     }
     return newReservoir.prefix(5).map { $0 }
 })
 .allSatisfy { $0 != ["ずん", "ずん", "ずん", "ずん", "どこ"] }
 .map { _ in  }
 .share()

let スピーカー = センサー付き水門.map { _ in "き・よ・し！" }
  .handleEvents(receiveOutput: { _ in
      print("（せーの...!）")
  })
  .delay(for: .seconds(1.0), scheduler: RunLoop.main)

let cancellable = ずんどこ水源
  .prefix(untilOutputFrom: センサー付き水門) // センサーが検知するまで、ずんどこを流す
  .merge(with: スピーカー) // 検知したら、き・よ・し！を流す
  .sink(receiveCompletion: { _ in
      print("===完===")
  }, receiveValue: {
      print("input: \($0)")
  })

import Cocoa
RunLoop.current.run(until: Date.now + 3 )