React fiber tree traversal

traversal.js

let root = $0._reactRootContainer._internalRoot

let node
let count
let map

node = root.current
count = 0
map = new Map()

while (node) {
  count++
  if (node.stateNode !== null)
  	map.set(node.stateNode, node)
 
  if (node.child === null) {
    while (node !== null && node.sibling === null)
    	node = node.return

    node = node?.sibling
    continue
  }

  node = node.child
}