d3 v4单击节点未折叠，文本未显示且工具提示错误

如何解决d3 v4单击节点未折叠，文本未显示且工具提示错误

https://jsfiddle.net/echilee/sqgjzf06/32/

请参阅我的问题的jsfiddle。当您单击任何节点时，您会看到链接重绘，并且节点没有崩溃，并且悬停时的工具提示存在错误。我也没有在节点旁边看到文本显示。 我想我缺少一些小东西。我将此d3v3转换为v4，并添加了新的.merge。不知道我在哪里缺少一个小的更改才能正常工作。需要另一双眼睛。这是@bryonymiles的一些不错的读物，在这里我了解了如何解决大多数合并问题。 https://medium.com/@bryony_17728/d3-js-merge-in-depth-a3069749a84f

var treeData = [{
  name: "null",children: [{
    "name": "Top Level_1","parent": "null","children": [{
      "name": "Level 2: A","parent": "Top Level_1","children": [{
        "name": "Son of A","parent": "Level 2: A"
      },{
        "name": "Daughter of A","parent": "Level 2: A"
      }]
    },{
      "name": "Level 2: B","parent": "Top Level"
    }],},{
    "name": "Top Level_2","children": [
    {
      "name": "Level 2_2: A","parent": "Top Level_2","children": [
      {
        "name": "Son of A_2","parent": "Level 2_2: A"
      },{
        "name": "Daughter of A_2","parent": "Level 2_2: A"
      }]
    },{
      "name": "Level 2_2: B","parent": "Top Level_2"
    }]
  }]
}];