How optimized are containers?

[chky-nmnsoftware]

Hello there. I am making a library for Pixi and I have my own custom parent-child system. As of right now, every leaf component has a parent container that allows it to have children. My question is, how much will this impact performance? In the old days, I believe that this would have a huge performance impact, so I'm curious what the impact is now with V8. Would it be better to just add / remove the container depending on the amount of children (so if an object is a single object, then it remains as such, but the moment a child is added, it gets put into a container and the container takes its place in the tree)? Any and all information helps. Thanks!