多个Publisher发布者数据流的整合
本小节演示使用CombineLatest与Merge将多个Publisher发布者数据流进行整合
示例一：CombineLatest会将发布者最新的数据进行整合
print("Demonstrating CombineLatest")
let usernamePublisher = PassthroughSubject<String, Never>()
let passwordPublisher = PassthroughSubject<String, Never>()
//: 整合最新的数据并进行验证
let validatedCredentialsSubscription = Publishers
.CombineLatest(usernamePublisher, passwordPublisher)
.map { (username, password) -> Bool in
!username.isEmpty && !password.isEmpty && password.count > 12
}
.sink { valid in
print("CombineLatest: are the credentials valid? \(valid)")
}
//: 输入1次用户名 2次密码
usernamePublisher.send("avanderlee")
passwordPublisher.send("weakpass")
passwordPublisher.send("verystrongpassword")输出：
Demonstrating CombineLatest
CombineLatest: are the credentials valid? false
CombineLatest: are the credentials valid? true示例二：Merge会将多个发布者的数据流合并为一个
print("Demonstrating Merge")
let publisher1 = [1,2,3,4,5].publisher
let publisher2 = [300,400,500].publisher
let mergedPublishersSubscription = Publishers
.Merge(publisher1, publisher2)
.sink { value in
print("Merge: subscription received value \(value)")
}输出：
Demonstrating Merge
Merge: subscription received value 1
Merge: subscription received value 2
Merge: subscription received value 3
Merge: subscription received value 4
Merge: subscription received value 5
Merge: subscription received value 300
Merge: subscription received value 400
Merge: subscription received value 500