example/expandable-tree/index.html

<head>
  <style> body { margin: 0; } </style>

  <script src="//cdn.jsdelivr.net/npm/force-graph"></script>
  <!--<script src="../../dist/force-graph.js"></script>-->

  <style>
    .clickable { cursor: unset !important }
  </style>
</head>

<body>
<div id="graph"></div>

<script type="module">
  import { forceCollide } from 'https://esm.sh/d3-force';
  import { csvParse } from 'https://esm.sh/d3-dsv';

  fetch('../datasets/d3-dependencies.csv').then(r => r.text()).then(csvParse).then(data => {
    const nodes = [], links = [];
    data.forEach(({ size, path }) => {
      const levels = path.split('/'),
        level = levels.length - 1,
        module = level > 0 ? levels[1] : null,
        leaf = levels.pop(),
        parent = levels.join('/');

      const node = {
        id: path,
        leaf,
        module,
        collapsed: level > 0,
        childLinks: []
      };

      nodes.push(node);

      if (parent) {
        links.push({ source: parent, target: path });
      }
    });

    const rootId = 'd3';

    // link parent/children
    const nodesById = Object.fromEntries(nodes.map(node => [node.id, node]));
    links.forEach(link => {
      nodesById[link.source].childLinks.push(link);
    });

    const getPrunedTree = () => {
      const visibleNodes = [];
      const visibleLinks = [];

      (function traverseTree(node = nodesById[rootId]) {
        visibleNodes.push(node);
        if (node.collapsed) return;
        visibleLinks.push(...node.childLinks);
        node.childLinks
          .map(link => ((typeof link.target) === 'object') ? link.target : nodesById[link.target]) // get child node
        .forEach(traverseTree);
      })(); // IIFE

      return { nodes: visibleNodes, links: visibleLinks };
    };

    const elem = document.getElementById('graph');
    const Graph = new ForceGraph(elem)
        .graphData(getPrunedTree())
        .nodeLabel('id')
        .nodeColor(node => !node.childLinks.length ? 'green' : node.collapsed ? 'red' : 'yellow')
        .onNodeHover(node => elem.style.cursor = node && node.childLinks.length ? 'pointer' : null)
        .onNodeClick(node => {
          node.collapsed = !node.collapsed; // toggle collapse state
          Graph.graphData(getPrunedTree());
        })
        .dagMode('td')
        .dagLevelDistance(90)
        .d3Force('collision', forceCollide(node => Graph.nodeRelSize()))
        .warmupTicks(250);
  });
</script>
</body>