agb1 wrote a reply+100 XP
4mos ago
I understood that this question posted quite long time ago, but, just in case, anyone still wants to use vue3-treeselect library with current Vue 3.x version without warning messages mentioned in initial message I could suggest to have a look at forked version - @cholakovdev/vue3-treeselect available for npm install as:
npm install --save @cholakovdev/vue3-treeselect
and source code available here: https://github.com/cholakovdev/vue3-treeselect
All credits goes to Anatoli, who updated original version and fixed annoying warning messages.