Clojurians Log v2

So this is fun, over in the f/mx project: • Background: I do not always worry about rebuilding all the widgets under a container if I just need to add or remove one; • MX does have an API for that, which btw goes further than just having a :key on each item; • in the f/mx TodoMVC, I did not worry about regenning all the children, I did so; • Problem: after adding a new todo, all existing todo view widgets misbehaved a couple of ways; • The misbehavior made me wonder if I was looking at Flutter items not aligned with the f/mx items; • Reading up on Flutter lifecycle and unmount, I saw internally it looked at the list view item :key to decide when to keep a widget; • I was using a Dart ValueKey based on the Todo's local storage key. Which does not change during the life of a Todo. Uh-oh! • I temporarily switched to UniqueKey and the app now works. Yay. • But now I have to swicth back to ValueKey and manage f/mx list view item proxies so they stay around and hopefully that will get F and F/mx on the same page. This should go in the wiki under Common Mistakes or sth

Interesting result on the Flutter "context" front: a little print diagnostic left in place to see if the context changes for a given f/mx widget build function now fires if we add or remove an item. This using a ValueKey on the unvarying storage-id. So, yeah, Flutter keeps the same internal structure, but it "moves" it to a new Element. Fun note: it does that for all subcomponents of the item as well.

OK, quiescing seems fine now that I am careful about reusing proxy items where Flutter will be reusing native items. This is what I was too lazy to write, costing me two days:

(map (fn [todo]
             (let [stg-id (td-stg-id todo)
                   exg (some (fn [li]
                               (when (= stg-id (.-value ^m/ValueKey (mget li :key)))
                                 li))
                         _cache)]
               (or exg (todo-list-item todo))))
        (sort-by todo/td-created-at
          (todo/app-todos (my-app))))