chart = {
const root = d3.hierarchy(data);
const links = root.links();
const nodes = root.descendants();
const simulation = d3.forceSimulation(nodes)
.force("link", d3.forceLink(links).id(d => d.id).distance(0).strength(1))
.force("charge", d3.forceManyBody().strength(-50))
.force("x", d3.forceX())
.force("y", d3.forceY())
.stop()
.tick(ticks);
const svg = d3.create("svg")
.attr("viewBox", [-width / 2, -height / 2, width, height]);
const link = svg.append("g")
.attr("stroke", "#999")
.attr("stroke-opacity", 0.6)
.selectAll("line")
.data(links)
.join("line");
const node = svg.append("g")
.attr("fill", "#fff")
.attr("stroke", "#000")
.attr("stroke-width", 1.5)
.selectAll("circle")
.data(nodes)
.join("circle")
.attr("fill", d => d.children ? null : "#000")
.attr("stroke", d => d.children ? null : "#fff")
.attr("r", 3.5);
node.append("title")
.text(d => d.data.name);
link
.attr("x1", d => d.source.x)
.attr("y1", d => d.source.y)
.attr("x2", d => d.target.x)
.attr("y2", d => d.target.y);
node
.attr("cx", d => d.x)
.attr("cy", d => d.y);
return svg.node();
}