CombineLatest extension for publisher array

CombineLatestArray.swift

// [publisher1, publisher2].combineLatest()
extension Array where Element: Publisher {
    func combineLatest() -> AnyPublisher<[Element.Output], Element.Failure> {
        Publishers.CombineLatestArray(self)
    }
}

// Publishers.CombineLatestArray([publisher1, publisher2])
extension Publishers {
    static func CombineLatestArray<P>(_ array: [P]) -> AnyPublisher<[P.Output], P.Failure> where P : Publisher {
        array.dropFirst().reduce(into: AnyPublisher(array[0].map{[$0]})) { res, ob in
            res = res.combineLatest(ob) { i1, i2 -> [P.Output] in
                return i1 + [i2]
            }.eraseToAnyPublisher()
        }
    }
}