This is an overview of the way a graph object with backwards refs is stored

graph.js

//Object -> Node -- constructor
let Node = (hash) => {
  this.id       = hash.id || new UUID()
  this.value    = hash
  this.parentId = null
  this.childIds = []
}

//-> Graph -- constructor
let Graph = () => {
  this.nodes = {}
}

/*
 * We always add the node to the graph before hooking up any relationships!
 * Here we are simply taking a list of nodes all of which have an ID and indexing
 * them in our graph structure.  We will then assign relationships by id
*/
//Graph -> Node -> Void
let addNode = (graph, node) => {
  graph.nodes[node.id] = node
}

//Graph -> String -> String -> Void
let attach = (graph, parentId, childId) => {
  graph.nodes[parentId].children.push(childId)
  graph.nodes[childId].parentId = parentId
}

//Graph -> String -> Void
let detach = (graph, nodeId) => {
  let parentId = graph.nodes[nodeId].parentId
  
  graph.nodes[parentId].children.pop(nodeId)
  graph.nodes[nodeId] = undefined
}

//(b -> Node) -> b -> Graph -> b
let reduce = (redFn, accum, graph) => {
  let keys = Object.keys(graph.node)
  
  for (for i = 0; i < keys.length; ++i){
    accum = redFn(accum, graph.nodes[keys[i]])
  }
  return accum
}