WiP: mechanism for persisting DOM across the tree in Mithril

domicile.js

import m from 'mithril'

const find = predicate => generator => {
  for(const item of generator)
    if(predicate(item))
      return item
}

const horizontalElementQuery = function * (root = document){
  const backlog = []

  if(root.children)
    for(child of root.children){
      yield child

      backlog.push(child)
    }
  
  for(child of backlog)
    yield * horizontalElementQuery(child)
}

const heap = new Map
const now  = new Map
const then = new Map

let root

const remap = () => {
  if(!root)
    root = find($ => $.vnodes, horizontalElementQuery())
  
  
}

const intercede = key => vnode => {
  if(!heap.size)
    setTimeout(remap)
  
  now.set(key, vnode)
}

export default ({key}, ...children) => {
  const intercession = 
    intercede(key)

  const vnode =
    m.fragment({
      oninit         : intercession,
      onbeforeupdate : intercession
    })
  
  heap.set(key, vnode)

  return vnode
}