vue结合D3.js并实现D3.js官网的Indented Tree的效果

要实现D3.js官网的Indented Tree的效果，我们需要先安装D3.js和Vue，并创建一个Vue项目。

安装D3.js：

npm install d3

创建Vue项目：

vue create my-project

然后在Vue项目中引入D3.js：

import * as d3 from 'd3';

接下来，我们可以在Vue组件中编写Indented Tree的代码。首先，我们需要定义数据。例如：

data() {
  return {
    treeData: {
      "name": "flare",
      "children": [
        {
          "name": "analytics",
          "children": [
            {
              "name": "cluster",
              "children": [
                {"name": "AgglomerativeCluster", "value": 3938},
                {"name": "CommunityStructure", "value": 3812},
                {"name": "HierarchicalCluster", "value": 6714},
                {"name": "MergeEdge", "value": 743}
              ]
            },
            {
              "name": "graph",
              "children": [
                {"name": "BetweennessCentrality", "value": 3534},
                {"name": "LinkDistance", "value": 5731},
                {"name": "MaxFlowMinCut", "value": 7840},
                {"name": "ShortestPaths", "value": 5914},
                {"name": "SpanningTree", "value": 3416}
              ]
            }
          ]
        },
        {
          "name": "animate",
          "children": [
            {"name": "Easing", "value": 17010},
            {"name": "FunctionSequence", "value": 5842},
            {
              "name": "interpolate",
              "children": [
                {"name": "ArrayInterpolator", "value": 1983},
                {"name": "ColorInterpolator", "value": 2047},
                {"name": "DateInterpolator", "value": 1375},
                {"name": "Interpolator", "value": 8746},
                {"name": "MatrixInterpolator", "value": 2202},
                {"name": "NumberInterpolator", "value": 1382},
                {"name": "ObjectInterpolator", "value": 1629},
                {"name": "PointInterpolator", "value": 1675},
                {"name": "RectangleInterpolator", "value": 2042}
              ]
            },
            {"name": "ISchedulable", "value": 1041},
            {"name": "Parallel", "value": 5176},
            {"name": "Pause", "value": 449},
            {"name": "Scheduler", "value": 5593},
            {"name": "Sequence", "value": 5534},
            {"name": "Transition", "value": 9201},
            {"name": "Transitioner", "value": 19975},
            {"name": "TransitionEvent", "value": 1116},
            {"name": "Tween", "value": 6006}
          ]
        }
      ]
    }
  }
}

然后，在Vue组件的`mounted`钩子函数中使用D3.js来创建Indented Tree：

mounted() {
  const width = 600;
  const height = 400;
  const margin = {top: 10, right: 120, bottom: 10, left: 40};
  const dx = 10;
  const dy = width / 6;
  const diagonal = d3.linkHorizontal().x(d => d.y).y(d => d.x);
  const tree = d3.tree().nodeSize([dx, dy]);
  const root = d3.hierarchy(this.treeData);
  root.x0 = dy / 2;
  root.y0 = 0;
  root.descendants().forEach((d, i) => {
    d.id = i;
    d._children = d.children;
    if (d.depth && d.data.name.length !== 7) d.children = null;
  });
  const svg = d3.select(this.$refs.tree).append('svg')
    .attr('viewBox', [-margin.left, -margin.top, width, dx])
    .style('font', '10px sans-serif')
    .style('user-select', 'none');
  const gLink = svg.append('g')
    .attr('fill', 'none')
    .attr('stroke', '#ccc')
    .attr('stroke-width', 1.5);
  const gNode = svg.append('g')
    .attr('cursor', 'pointer')
    .attr('pointer-events', 'all');
  function update(source) {
    const duration = d3.event && d3.event.altKey ? 2500 : 250;
    const nodes = root.descendants().reverse();
    const links = root.links();
    tree(root);
    let left = root;
    let right = root;
    root.eachBefore(node => {
      if (node.x < left.x) left = node;
      if (node.x > right.x) right = node;
    });
    const height = right.x - left.x + margin.top + margin.bottom;
    const transition = svg.transition()
      .duration(duration)
      .attr('viewBox', [-margin.left, left.x - margin.top, width, height])
      .tween('resize', window.ResizeObserver ? null : () => () => svg.dispatch('toggle'));
    const node = gNode.selectAll('g')
      .data(nodes, d => d.id);
    const nodeEnter = node.enter().append('g')
      .attr('transform', d => `translate(${source.y0},${source.x0})`)
      .attr('fill-opacity', 0)
      .attr('stroke-opacity', 0)
      .on('click', d => {
        d.children = d.children ? null : d._children;
        update(d);
      });
    nodeEnter.append('circle')
      .attr('r', 2.5)
      .attr('fill', d => d._children ? '#555' : '#999')
      .attr('stroke-width', 10);
    nodeEnter.append('text')
      .attr('dy', '0.31em')
      .attr('x', d => d._children ? -6 : 6)
      .attr('text-anchor', d => d._children ? 'end' : 'start')
      .text(d => d.data.name)
      .clone(true).lower()
      .attr('stroke-linejoin', 'round')
      .attr('stroke-width', 3)
      .attr('stroke', 'white');
    const nodeUpdate = node.merge(nodeEnter).transition(transition)
      .attr('transform', d => `translate(${d.y},${d.x})`)
      .attr('fill-opacity', 1)
      .attr('stroke-opacity', 1);
    const nodeExit = node.exit().transition(transition).remove()
      .attr('transform', d => `translate(${source.y},${source.x})`)
      .attr('fill-opacity', 0)
      .attr('stroke-opacity', 0);
    nodeExit.select('circle').attr('r', 1e-6);
    nodeExit.select('text').style('fill-opacity', 1e-6);
    const link = gLink.selectAll('path')
      .data(links, d => d.target.id);
    const linkEnter = link.enter().append('path')
      .attr('d', d => {
        const o = {x: source.x0, y: source.y0};
        return diagonal({source: o, target: o});
      });
    const linkUpdate = link.merge(linkEnter).transition(transition)
      .attr('d', diagonal);
    link.exit().transition(transition).remove()
      .attr('d', d => {
        const o = {x: source.x, y: source.y};
        return diagonal({source: o, target: o});
      });
    root.eachBefore(d => {
      d.x0 = d.x;
      d.y0 = d.y;
    });
  }
  update(root);
}

最后，在Vue组件的模板中添加一个`div`元素，用来渲染Indented Tree：

<template>
  <div ref="tree"></div>
</template>

这样，我们就可以在Vue项目中使用D3.js来实现Indented Tree的效果了。