Investigate a better node-counting solution

[thomasboyt]

The core issue with ReactDOMFragment is that is the rendered component of a ReactCompositeComponent. It is, as best I can tell, impossible to access composite component from the DOM fragment, meaning it's impossible to update the nodeCount of the composite component.

This leads to the following issues:

1. If the number of children in a fragment change, the fragment's composite component nodeCount is not updated
2. The composite component cannot simply access the renderedComponent's nodeCount because the rendered component is removed during the removal cycle, before removeChild is called

Possible better ways to store node counts:

• A global(ish? maybe looked up somehow?) map of node counts, keyed by React ID. This feels like a hack, but would cut through the lifecycle issues.
• Do some next-level refactoring of ReactCompositeComponent to make it somehow support multiple root nodes at a higher level
  • Fragments return markup as an array; could simply look at the type of markup returned
  • What does the update cycle look like at this level? This doesn't seem to solve problem 1) above.
  • If ReactCompositeComponent truly becomes multiple-component aware, <frag> could almost become a no-op that simply makes sure an array of nodes is passed in to the composite component...

[thomasboyt]

The thing I keep coming back to is problem 2 above. It seems like such a fixable thing, and using a map to get around it seems like such a massive hammer to apply to a tiny problem.

[thomasboyt]

Managed to work around point 2 for now by storing on the CompositeComponent