const stacks = new Map()
visitParents(tree, (node, parents) => {
 if (nodesToFind.includes(node)) {
 stacks.set(node, parents)
 }
})
nodesToFind.forEach(node => {
 if (!stacks.has(node)) {
 throw new Error('unist-util-ancestor requires all nodes be contained in the tree')
 }
})
// Somethign like this?
let index = -1
let ancestor = tree
// This is broken, maybe you get the gist?
while (++index) {
 const nextAncestor = stacks.get(nodesToFind[0])[index]
 const shared = nodesToFind.every(node => stacks.get(node)[index] === nextAncestor)
 // To do: exit if there are no nodes left on stacks.
 if (shared) {
 ancestor = nextAncestor
 } else {
 break
 }
}