PaginationModifier.swift

struct PaginationModifier: ViewModifier {
    let metadata: PaginationMetadata?
    let onBottom: () -> Void

    func body(content: Content) -> some View {
        content
        if let metadata, !metadata.isAtEnd, metadata.items != 0 {
            VStack {
                Text("Page \(metadata.page) of \(metadata.pages).")
                Text("\(metadata.items) total items.")
                ProgressView()
            }
            .onAppear(perform: { onBottom() })
            .font(.caption)
        }
    }
}

extension View {
    func paginate(pagination: PaginationMetadata?, _ perform: @escaping () -> Void) -> some View {
        self.modifier(PaginationModifier(metadata: pagination, onBottom: perform))
    }
}