[aranchelk]

> Depending on the use case, the state of features like user selection, user page selection, user zoom setting, etc. could be included in the undo/redo stack to provide a great experience.

Does anyone have an idea what these use cases could be? My mental model for undo/redo is based on productivity applications and I’m at a loss; I’m genuinely curious though since this is something I’ve been implementing.

[hamtr]

In design tools, like Figma, undo sometimes just walks backwards through your selection (even if you didn't change anything). It'll even switch between pages. I'm interesting in seeing if there are other ones people can bring up

[guillaumesalles]

For rich text editing, undo should probably reset the scroll position and the cursor close the edit you're undoing.

I think reseting the time position would also make sense for video editing.

So basically, it's a way to get back as much as possible in the context you were at the time of the operation that is undone.

[aranchelk]

Thank you, this is both a good and nuanced example.

It would likely be a better UX if that scrolling (etc) brought the user back to the exact context they made that edit, but in the interest of laziness and impatience I'm just using a generic focus function.

It might be nice to have more exact context data available for the life of a session as a progressive enhancement, though I think it would have to be a clever encoding, else that data would be invalid in cases such as window resizes and edits made by collaborators that change position of the object being edited.

[aranchelk]

Interesting, that's a really good one, thank you.

Now that I'm thinking about it, when I used to use Autodesk Fusion 360 I think it did this a bit, but until now I thought it was just another bug: they had accidentally added some UI state changes to the undo stack.

[solardev]

Google Maps is one such example. Every time you click on something, change the zoom, toggle the layers, etc., it gets saved to state (and persisted to the URL). That way you can use your browser back/forward buttons to switch between different places or views of places, and also share that with your friends.

Miro (the collaborative whiteboard)/Figjam is another... the boards can grow pretty big in x-y space, and losing your place in space is very easy to do, especially if you ctrl-z a few times and forget what you were even working on. Just knowing that "somewhere on this board, something changed" isn't helpful if you can't see what it was.

Analytics is another such use case, for when you're composing queries or search filters, date ranges, etc. Google Analytics does something similar by giving each set of criteria its own unique URL, so that you can use the back/forward in your browser to go between states. Not exactly the same as an undo/redo button, but pretty much the same idea.

Another example: I work for a solar company, and we're building a web app that equipment installers can use to monitor the performance of rooftop solar arrays they've installed. It tracks, for example, each solar module's power production on a heatmap, arranged in the same layout as on the actual roof. There's a lot of interaction that can happen... selecting a particular unit, choosing a particular timeframe, deciding which metric you want to look at, search terms, table filters, sort order, etc.

None of that needs to be written to our database as actual changes to the layout and device pairings. But it would still be handy handy for users to be able to undo/redo, bookmark, permalink, etc.

I think of it this way: A set of UI states like that, taken as a whole, is in and of itself a form of "data"... it is a human user's carefully framed view of some point in time, and some selection of data, that they have deemed important. Being able to save and retrieve that state in case they make a mistake (cat jumped on the mouse) or want to share it with others ("hey, check out what's happening to this module on X date at 4pm") is helpful, even if it doesn't ever need to be written to the server (since it can be stored as local state and/or URL strings).