Feature request: expose how many matches there are when filtered

[cers]

This could be something like onSearchComplete or similar, accepting a function that is called when a search completes, passing along the number of matching nodes

[jameskerr]

That's a good idea. Thanks for the suggestion. I think it would also be good to put in the TreeApi as a method. We currently have an .isFiltered boolean getter. Maybe another could be filteredCount.