ReactiveSwift | Streams of values over time | Reactive Programming library

There's no type mistake. You are printing out the Observable itself, not the values that the Observable emits. So what you see in the print output is the description of the Observable.

All you need to achieve what you want is:

Purely from a reactive programming perspective, I understand why the second approach is attractive. But the nature of UITableView is such that you really need to involve the table in row updates. The easiest way to do this is by using using the new-fangled UITableViewDiffableDataSource introduced in iOS 13, but if you're not using that then must call either reloadData or reloadRows(at:) to tell the table to update all rows or specific rows when their data changes.

If you subscribe each cell then it might appear to work in certain or most situations, but if you ever have a data update that changes the height of a cell (e.g. by displaying longer text in a label and causing it to wrap to a second line) then the cell will not resize properly because the table doesn't know that the row was updated.

I agree with you that it is unpleasant that rows can't manage their own updates in a perfectly self-contained manner, but UITableView works that way for performance reasons as far as I understand.

This was a change made in newer ReactiveSwift versions. Instead of returning a disposable, you should add it to the lifetime passed to the closure:

I think the reason your second flatMap is never executed is that saveSignal never sends a value; it just finishes with a completed event or an error event. That means map will never be called, and no values will ever be passed to your second flatMap. You can fix it by doing something like this:

I'm don't know exactly what successfullyUploaded and failedToUpload are doing in your code, but presumably you're keeping track of successes and failures to provide some kind of live progress UI. This is how I would structure it:

I'm not completely familiar with ReactiveSwift/ReactiveCocoa, but based on your description, you can use .scan, which seems to be a more general function than combinePrevious.

It takes an initial result - which you can make into a tuple -, and a closure with the stored value and the current value, and returns a new stored value - in your case, a tuple with (previous, current):

You can always create a custom Publisher for your needs. For example, here I've created TextField publisher, that wraps textFieldDidChange action for textField and sends String after each character entered/deleted! Please, copy the link, SO doesn't parse it:

https://github.com/DmitryLupich/Combine-UIKit/blob/master/CombineCustomPublishers/%20Publishers/TextFieldPubisher.swift