Cocoa offers the same undo implementation as described here with "NSUndoManager" where, for each action, you add the opposite action to an undo stack. As a pat

Cocoa offers the same undo implementation as described here with "NSUndoManager" where, for each action, you add the opposite action to an undo stack. As a pattern it is proven to work. It just consumes memory and servers might not scale as well as a desktop app in this regard. If the undo/redo stacks don't grow too long and the operations are simple enough in nature it might work though.