chart = {
const fisheye = fisheyeO.circular()
.radius(100)
.distortion(5);
const simulation = d3.forceSimulation(nodes)
.alphaDecay(0.125)
.alphaMin(0.01)
.force("link", d3.forceLink(links).id(d => d.id))
.force("charge", d3.forceManyBody())
.force("x", d3.forceX(width/2))
.force("y", d3.forceY(height/2));
const svg = d3.create("svg")
.attr("viewBox", [0, 0, width, height])
.on("mousemove", d=>fisheye.focus(d3.mouse(this)));
const link = svg.append("g")
.attr("stroke", "#999")
.attr("stroke-opacity", 0.6)
.selectAll("line")
.data(links)
.join("line")
.attr("stroke-width", 2);
const node = svg.append("g")
.attr("stroke", "#fff")
.attr("stroke-width", 1.5)
.selectAll("circle")
.data(nodes)
.join("circle")
.attr("r", 5)
.attr("fill", "black")
.call(drag(simulation));
node.append("title")
.text(d => d.id);
svg.on("mousemove", function() {
fisheye.focus(d3.mouse(this));
node.each(function(d) { d.fisheye = fisheye(d); })
.attr("cx", function(d) { return d.fisheye.x; })
.attr("cy", function(d) { return d.fisheye.y; })
.attr("r", function(d) { return d.fisheye.z * 4.5; });
link.attr("x1", function(d) { return d.source.fisheye.x; })
.attr("y1", function(d) { return d.source.fisheye.y; })
.attr("x2", function(d) { return d.target.fisheye.x; })
.attr("y2", function(d) { return d.target.fisheye.y; });
})
simulation.on("tick", () => {
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();
}