How use Notification in RxSwift

ObservableType+Ben.swift

extension ObservableType {

    func postNotification(_ name: Notification.Name) -> Observable<E> {
        return self.do(onNext: { element in
            NotificationCenter.default.post(name: name, object: element)
        })
    }
}

/////////
//Usage//
/////////

extension Notification.Name {
    static let createCategory = Notification.Name("createCategory")
    static let editCategorty = Notification.Name("createCategory")
}

func createCategory(with name: String) -> Observable<ClipCategory> {
    return categoryAPI
        .createCategory(with: name)
        .postNotification(.createCategory)
}

NotificationCenter.default.rx.notification(.createCategory)
    .map { _ in () }
	.bind(to: fetchCategory)
	.disposed(by: disposeBag)

Why would you post a notification and return an observable? It is already using the Observer pattern. You just need to listen with rx.notification