previousSelectedItemsRef.current is not updated

[boris-brtan]

downshift/src/hooks/useMultipleSelection/index.js

Line 81 in 90d6d72

}, [selectedItems.length])

in some special cases for multiple selection when we use setSelectedItems instead of addSelectedItem, it can happen that previousSelectedItemsRef.current is not updated because setSelectedItems sets the same amount of items but different.

Example

1, 2, 3, 4
set 2, 3
set 1, 4
but in previousSelectedItemsRef.current are still 2, 3
set 1, 2, 3
in previousSelectedItemsRef.current are 1,2,3 because length changed

[boris-brtan]

is this something that can be fixed or do you need Pull Request to be created?

[silviuaavram]

It is a corner case, but still valid. On the other hand, the alternative would be to search for potentially removed items on every render. Any better suggestions?

Furthermore, this hook logic is to announce to screen readers when an item is removed. It needs a completely different logic in order to handle the case with setSelectedItems.

I am still thinking about a better way with the whole a11y screen reader announcements, since the current behaviour is not great. I will update once we figure out something.

[boris-brtan]

tried something, it is not perfect however better than nothing.