export function TopologicalSorter () {
  const graph = {}
  let isVisitedNode
  let finishTimeCount
  let finishingTimeList
  let nextNode

  this.addOrder = function (nodeA, nodeB) {
    nodeA = String(nodeA)
    nodeB = String(nodeB)
    graph[nodeA] = graph[nodeA] || []
    graph[nodeA].push(nodeB)
  }

  this.sortAndGetOrderedItems = function () {
    isVisitedNode = Object.create(null)
    finishTimeCount = 0
    finishingTimeList = []

    for (const node in graph) {
      if (Object.prototype.hasOwnProperty.call(graph, node) && !isVisitedNod