Method Chaining

method-chaining.swift

// MARK: Method chaining

class MethodChainig {
    func fetchImage() -> Fetch<UIImage> {
        let fetch = Fetch<UIImage>()
        return fetch
    }
    
}

class Fetch<T> {
    func onSuccess(succeed : T -> ()) -> Self {
        return self
    }
    
    func onFailure(fail : NSError? -> ()) -> Self {
        return self
    }
}

let example4 = MethodChainig()

example4.fetchImage().onSuccess { image in
    // success
}

example4.fetchImage().onFailure { error in
    // Failure
}.onSuccess { image in
    // Success
}