hyperapp: Transitions broken in 1.2.6

Between 1.2.5 and 1.2.6, this snippet was introduced in the child-patching algorithm:

        if (newKey != null && newKey === getKey(oldChildren[i + 1])) {
          if (oldKey == null) {
            removeElement(element, oldElements[i], oldChildren[i])
          }
          i++
          continue
        }

In cases where all children are keyed, and the first one is removed, I believe this somehow causes onupdate not to be called for the rest of the children. (Not exactly sure how yet)

Why do I think this?

The behavior can be observed in the “Toasts” example of @hyperapp/transitions: https://codepen.io/zaceno/pen/QOYOZd

Add a few messages (like five) Click the messages away from the top.

Notice that the remaining children don’t slide up smoothly as they should. Rather they skip up immediately. This means that the Move transition isn’t being triggered.

Also, notice that the fade-out animation for removed toasts doesn’t occur from their current position at the top, but from their original position (before you started removing them). This tells me that the position-tracking isn’t being triggered either.

Both the Move transition and position tracking are triggered by the onupdate lifecycle method. So my conclusion is that onupdate is not being called.

Cross-reference: https://github.com/hyperapp/transitions/issues/19