WWDC.2019.Combine.ops.swift

func run () {
    if #available(iOS 13.0, *) {
        
        // Create
        let p1 = Publishers.Empty<Int, Error>()
        let p2 = Publishers.Just(42)
        let p3 = Publishers.Sequence<[Int], Error>(sequence: [1,2,3,4])
        
        // Operators
        let p4 = p1
            .merge(with: p2)
            .append(5) // add 5 to the end of the sequence
            .allSatisfy { $0 >= 1 } // check if all values are bigger than 0
            .count() // how many values: 1
    }
}