找不到D3js Force Directed Graph Link

Question

我目前正在尝试用d3js v4构建一个力导向图.我有以下节点和链接,实际上非常简单

节点

[
  {
    "id":"4d2b0275-5bc7-e611-81c4-00155df7ea33"
  },{
    "id":"b32b0275-5bc7-e611-81c4-00155df7ea33"
  }
]

链接

[
  {
    "source":"4d2b0275-5bc7-e611-81c4-00155df7ea33",
    "target":"b32b0275-5bc7-e611-81c4-00155df7ea33"
  }
]

我的forceSimulation设置是

var simulation = d3.forceSimulation(nodes)
    .force("charge", d3.forceManyBody())
    .force("link", d3.forceLink(links).distance(20).strength(1))
    .force("x", d3.forceX())
    .force("y", d3.forceY())
    .stop()

它会在d3.forceLink(链接)上引发错误Uncaught Error: missing: 4d2b0275-5bc7-e611-81c4-00155df7ea33.那么为什么这个错误因为链接实际上存在？

Answer 1

在D3中,默认的link.id()访问器函数:

允许将每个链接的源和目标指定为节点数组中从零开始的索引.

这意味着源和目标由节点的索引定义,如API中的此示例所示:

var links = [
    {"source": 0, "target": 1}, //from the first node to the second
    {"source": 1, "target": 2} //from the second node to the third
];

但是,由于您要通过id节点而不是数字索引来定义源和目标,因此必须在id()函数中指定此id :

.force("link", d3.forceLink(links)
     .id(function(d,i) {
         return d.id
     })
    .distance(20)
    .strength(1)
)