JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/3.5.5/d3.min.js"></script>
<h1>Help please!</h1>

CSS

.link {
  stroke: #000;
  stroke-width: 1.5px;
}

.node {
  fill: #000;
  stroke: #fff;
  stroke-width: 1.5px;
}

.node.a { fill: #1f77b4; }
.node.b { fill: #ff7f0e; }
.node.c { fill: #2ca02c; }

JavaScript

var width = 450,
    height = 500;

var color = d3.scale.category10();

var nodes = [],
    links = [];

var force = d3.layout.force()
    .nodes(nodes)
    .links(links)
    .charge(-400)
    .linkDistance(120)
    .size([width, height])
    .on("tick", tick);

var svg = d3.select("body").append("svg")
    .attr("width", width)
    .attr("height", height);

var node = svg.selectAll(".node");
    link = svg.selectAll(".link");

// 1. Add three nodes and three links.
setTimeout(function() {
  var a = {id: "a"}, b = {id: "b"}, c = {id: "c"};
  nodes.push(a, b, c);
  links.push({source: a, target: b}, {source: a, target: c}, {source: b, target: c});
  start();
}, 0);

// 2. Remove node B and associated links.
setTimeout(function() {
  nodes.splice(1, 1); // remove b
  links.shift(); // remove a-b
  links.pop(); // remove b-c
  start();
}, 3000);

// Add node B back.
setTimeout(function() {
  var a = nodes[0], b = {id: "b"}, c = nodes[1];
  nodes.push(b);
  links.push({source: a, target: b}, {source: b, target: c});
  start();
}, 6000);

function start() {
  link = link.data(force.links(), function(d) { return d.source.id + "-" + d.target.id; });
  link.enter().insert("line", ".node").attr("class", "link");
  link.exit().remove();

 node = node.data(force.nodes(), function(d) { return d.id;});

  // Append a group element
  group = node.enter().append("g").call(force.drag);

  // Append circle to the group element
  group.append("circle")
    .attr("class", function(d) { return "node " + d.id; })
    .attr("r", 8);

  // Append text to the group element
  group.append("text").text(function(d) { return d.id ;});  
  
  // Transform the group to proper location
  group.attr("transform", function(d) {
    return 'translate(' + [d.x, d.y] + ')';
  });

  node.exit().remove();

  force.start();
}

function tick() {
//  node.attr("cx", function(d) { return d.x; })
//      .attr("cy", function(d) { return d.y; })
  node.attr("transform", function(d) {
    return...