Inconsistency with setItemIndex and Navigator / World state

When calling setItemIndex inside a add-item callback, there is an inconsistency in the World and Navigator states. The former has the item that triggered the add-item callback, but World does not.

So, given this use case:

• add an item with viewer.addTiledImage
• code in add-item callback inspects world._items and determines that one of the items needs to be moved to top of the list, so it calls setItemIndex
• setItemIndex updates World state, and dispatches the item-index-change event
• item-index-change fires.

However, since the Navigator state does not yet have the item from add-item, an error is thrown:

Uncaught Error: Index bigger than number of layers.

I’m not sure if this matters in our use case, since the Navigator state eventually does include the item, it is just in a different ordering than World. However, I think the expected behavior would be that state for both would be updated when the add-item callback fires.

[iangilman]

Good catch! I guess to fix it we would have to make sure the navigator gets the add item event before anyone else.

Meanwhile a workaround could be putting a setTimeout of 1 in your add-item handler, to give the chance for the navigator to catch up.

Thank you for reporting this! If you’re interested in working on a fix, I’m happy to answer any questions you have along the way. Otherwise hopefully someone will take an interest in it.

[iangilman]

Fixed by #2005