D3（React）中的节点和链接：如何通过我的链接连接节点？

Question

We're trying to connect our nodes but it doesn't work. The nodes are beeing displayed but not their connections(links).

This is our code:

 CreateNodesAndLinks() {
    let canvas = d3.select(this.refs.anchor)
    let width = 800
    let height = 600


    let companyNodes = Object.values(this.state.data.CompanyNodes)
    let links = Object.values(this.state.data.Links)

    companyNodes = this.filter_array_values(companyNodes)
    links = this.filter_array_values(links)

    console.log(companyNodes)
    console.log(links)

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

    const svg = canvas.append("svg")
      .attr("viewBox", [0, 0, width, height]);

    const link = svg.append("g")
      .attr("stroke", "#999")
      .attr("stroke-opacity", 0.6)
      .selectAll("line")
      .data(links)
      .join("line")
      .attr("stroke-width", item => Math.sqrt(item.percent_share));

    const companyNode = svg.append("g")
      .attr("stroke", "#fff")
      .attr("stroke-width", 1.5)
      .selectAll("circle")
      .data(companyNodes)
      .join("circle")
      .attr("r", 5)
      .attr("fill", "black")
      .call(this.drag(simulation));

    companyNode.append("title")
      .text(item => item.company_id);

    simulation.on("tick", () => {
      link
        .attr("x1", d => d.from_id.x)
        .attr("y1", d => d.from_id.y)
        .attr("x2", d => d.to_id.x)
        .attr("y2", d => d.to_id.y);

      companyNode
        .attr("cx", d => d.x)
        .attr("cy", d => d.y);
    });

    return svg.node();
  }

render function:

  render() {

    return (
        <div>

          <g ref="anchor" />

        </div>
    );
  }

And this is how our companyNodes and links Object looks like: https://ibb.co/b5bsRLg

So the connection is between "from_id" and "to_id"

And we don't know what we're doing wrong. Maybe someone can help

Probably there's something wrong with the

simulation.on("tick", () => {
          link...

method but we can't figure it out.

Answer 1

We found our mistakes and maybe it could help someone.

This...

 const simulation = d3.forceSimulation(companyNodes)
          .force("link", d3.forceLink(links))

...had to be changed to this:

 const simulation = d3.forceSimulation(companyNodes)
      .force("link", d3.forceLink(links).id(d => d.company_id))  //company_id is the identifier for one specific company we have in companyNodes

And the other thing was that we had to rename every from_id to source and to_id to target because it seems like d3 is only working with source and target