我-w=10=sh

Question

所以我正试图将这个很好的例子作为目标Force-Directed Graph for some very simple json: https://raw.githubusercontent.com/DealPete/forceDirected/master/countries.json

我的作品在这里：codepen

我从 d3 得到源源不断的错误，一开始没有错误提示我的代码有问题。开头是这样的：

XHR finished loading: GET "https://raw.githubusercontent.com/DealPete/forceDirected/master/countries.json".
[...]
d3.min.js:2 Uncaught Error: missing: 0
    at ar (d3.min.js:2)
    at r (d3.min.js:5)
    at Function.e.links (d3.min.js:5)
    at pen.js:46
    at Object.<anonymous> (d3.min.js:7)
    at d.call (d3.min.js:4)
    at XMLHttpRequest.e (d3.min.js:7)
ar @ d3.min.js:2
r @ d3.min.js:5
e.links @ d3.min.js:5
(anonymous) @ pen.js:46
(anonymous) @ d3.min.js:7
call @ d3.min.js:4
e @ d3.min.js:7
d3.min.js:5 Uncaught TypeError: Cannot create property 'vx' on number '66'
    at e (d3.min.js:5)
    at d3.min.js:5
    at Fe.each (d3.min.js:5)
    at e (d3.min.js:5)
    at n (d3.min.js:5)
    at yn (d3.min.js:2)
    at gn (d3.min.js:2)
e @ d3.min.js:5
(anonymous) @ d3.min.js:5
each @ d3.min.js:5
e @ d3.min.js:5
n @ d3.min.js:5
yn @ d3.min.js:2
gn @ d3.min.js:2
d3.min.js:5 Uncaught TypeError: Cannot create property 'vx' on number '66'
    at e (d3.min.js:5)
    at d3.min.js:5
    at Fe.each (d3.min.js:5)
    at e (d3.min.js:5)
    at n (d3.min.js:5)
    at yn (d3.min.js:2)
    at gn (d3.min.js:2)
e @ d3.min.js:5
(anonymous) @ d3.min.js:5
each @ d3.min.js:5
e @ d3.min.js:5
n @ d3.min.js:5
yn @ d3.min.js:2
gn @ d3.min.js:2

我实际上无法在 d3 v4+ 中找到关于力图的良好介绍资源，所以我必须破解它。

html

<main>
  <section class="d3">
  </section>
</main>

代码

const api = 'https://raw.githubusercontent.com/DealPete/forceDirected/master/countries.json' 

let root = d3.select(".d3"),
    width = +root.attr("width"),
    height = +root.attr("height")

let svg = root.append('svg')
    .attr("width", width)
    .attr("height", height)

let color = d3.scaleOrdinal(d3.schemeCategory20);

let simulation = d3.forceSimulation()
    .force("link", d3.forceLink().id((d) => d.country))
    .force("charge", d3.forceManyBody())
    .force("center", d3.forceCenter(width / 2, height / 2));

d3.json(api, function(error, graph) {
  if (error) 
    throw error

  let link = svg.append("g")
    .attr("class", "links")
    .selectAll("line")
    .data(graph.links)
    .enter().append("line")
    .attr("stroke-width",  () => 4);

  let node = svg.append("g")
    .attr("class", "nodes")
    .selectAll("circle")
    .data(graph.nodes)
    .enter().append("circle")
    .attr("r", 5)
    .attr("fill", d => color(1))
    .call(d3.drag()
      .on("start", dragstarted)
      .on("drag", dragged)
      .on("end", dragended))

  simulation
    .nodes(graph.nodes)
    .on("tick", ticked)

  simulation.force("link")
    .links(graph.links)

  function ticked() {
    link
        .attr("x1", function(d) { return d.source.x; })
        .attr("y1", function(d) { return d.source.y; })
        .attr("x2", function(d) { return d.target.x; })
        .attr("y2", function(d) { return d.target.y; });

    node
        .attr("cx", function(d) { return d.x; })
        .attr("cy", function(d) { return d.y; });
  }
})

function dragstarted(d) {
  if (!d3.event.active) simulation.alphaTarget(0.3).restart();
  d.fx = d.x;
  d.fy = d.y;
}

function dragged(d) {
  d.fx = d3.event.x;
  d.fy = d3.event.y;
}

function dragended(d) {
  if (!d3.event.active) simulation.alphaTarget(0);
  d.fx = null;
  d.fy = null;
}

Answer 1

看看你的 links 数组：

[
    { "target": 66, "source": 0 },
    { "target": 3, "source": 1 },
    { "target": 100, "source": 2 },
    ...
]

现在看看你的 id 函数：

.id((d) => d.country)

如您所见，links 数组中没有 country。

因此，由于您正在为链接使用 数字索引 ，只需删除 id() 函数即可。根据 API:

If id is specified, sets the node id accessor to the specified function and returns this force. If id is not specified, returns the current node id accessor, which defaults to the numeric node.index

这是您的工作代码：

const api = 'https://raw.githubusercontent.com/DealPete/forceDirected/master/countries.json'

var width = 500,
  height = 500;

let svg = d3.select("body").append('svg')
  .attr("width", width)
  .attr("height", height)

let color = d3.scaleOrdinal(d3.schemeCategory20);

let simulation = d3.forceSimulation()
  .force("link", d3.forceLink())
  .force("charge", d3.forceManyBody())
  .force("center", d3.forceCenter(width / 2, height / 2));

d3.json(api, function(error, graph) {
  if (error)
    throw error

  let link = svg.append("g")
    .attr("class", "links")
    .selectAll("line")
    .data(graph.links)
    .enter().append("line")
    .attr("stroke", "black")
    .attr("stroke-width", 4);

  let node = svg.append("g")
    .attr("class", "nodes")
    .selectAll("circle")
    .data(graph.nodes)
    .enter().append("circle")
    .attr("r", 5)
    .attr("fill", d => color(1))
    .call(d3.drag()
      .on("start", dragstarted)
      .on("drag", dragged)
      .on("end", dragended))

  simulation
    .nodes(graph.nodes)
    .on("tick", ticked)

  simulation.force("link")
    .links(graph.links)

  function ticked() {
    link
      .attr("x1", function(d) {
        return d.source.x;
      })
      .attr("y1", function(d) {
        return d.source.y;
      })
      .attr("x2", function(d) {
        return d.target.x;
      })
      .attr("y2", function(d) {
        return d.target.y;
      });

    node
      .attr("cx", function(d) {
        return d.x;
      })
      .attr("cy", function(d) {
        return d.y;
      });
  }
})

function dragstarted(d) {
  if (!d3.event.active) simulation.alphaTarget(0.3).restart();
  d.fx = d.x;
  d.fy = d.y;
}

function dragged(d) {
  d.fx = d3.event.x;
  d.fy = d3.event.y;
}

function dragended(d) {
  if (!d3.event.active) simulation.alphaTarget(0);
  d.fx = null;
  d.fy = null;
}

<script src="https://d3js.org/d3.v4.min.js"></script>

我-w=10=sh

d3 - "Cannot create property 'vx' on number '65'"

json

directed-graph

d3.js

d3-force-directed

html

代码