Useful URL extensions

URLExtensions.swift

extension URL {
    typealias ComponentsManipulator = (inout URLComponents) -> ()

    func manipulate(with manipulator: ComponentsManipulator) -> URL {
        guard var components = URLComponents(url: self, resolvingAgainstBaseURL: true) else { return self }
        manipulator(&components)
        return components.url ?? self
    }

    /// Deletes first path component after the initial slash
    /// For example, path /en/v1/sync/categories becomes /v1/sync/categories
    func deletingFirstPathComponent() -> URL {
        return manipulate { components in
            components.path = "/" + pathComponents.dropFirst().dropFirst().joined(separator: "/") // drop initial "/" first
        }
    }

    /// Adds or replaces a query parameter
    func settingParameter(named name: String, to value: CustomStringConvertible) -> URL {
        return manipulate { components in
            var items = components.queryItems?.filter { $0.name != name } ?? []
            items.append(URLQueryItem(name: name, value: String(describing: value)))
            components.queryItems = items
        }
    }
}