Transitions with D3

Avoid restarting running transitions by either starting one just on the .enter() selection or by using selection.filter() to only select elements which are not in transit yet.

Alternative implementations combining D3 with React and React TransitionGroup.

<!DOCTYPE html>
<meta charset="utf-8">
<style>
body {
  background: #fff;
}

.item {
  fill: none;
  stroke-width: 1.5;
}
</style>
<body>
<script src="https://d3js.org/d3.v3.min.js"></script>
<script>

var width = 960,
    height = 500,
    data = [];

var x = d3.scale.linear()
  .domain([0, 1])
  .range([0, width]);

var y = d3.scale.linear()
  .domain([0, 1])
  .range([150, height - 150]);

var r = d3.scale.sqrt()
  .domain([0, 1])
  .range([0, 30]);

function render() {
  // Make sure the SVG element only gets created once.
  var svg = d3.select('body').selectAll('svg').data([0]);
  svg.enter().append('svg')
    .attr('width', width)
    .attr('height', height);

var item = svg.selectAll('circle')
    .data(data, function(d) { return d.key; });

item.enter().append('circle')
    .attr('class', 'item')
    .attr('r', function(d) { return r(d.r); })
    .attr('cx', function(d) { return x(d.x); })
    .attr('cy', 0)
    .style('stroke', '#3E6E9C')
  .transition().duration(1000)
    .attr('cy', function(d) { return y(d.y); })
    .style('stroke', '#F288A5');

item.exit().filter(':not(.exiting)') // Don't select already exiting nodes
    .classed('exiting', true)
  .transition().duration(1000)
    .attr('cy', height)
    .style('stroke', '#3E6E9C')
    .remove();
}

var circlesCreated = 0;

function add() {
  data.push({key: Date.now(), x: Math.random(), y: Math.random(), r: Math.random()});
  render();
  setTimeout(data.length < 100 ? add : remove, 5);
}

function remove() {
  data = data.slice(1);
  render();
  if (++circlesCreated === 1000) console.timeEnd('1000 circles');
  setTimeout(data.length > 0 ? remove : add, 5);
}

console.time('1000 circles');
add();

</script>

Modified http://d3js.org/d3.v3.min.js to a secure url

https://d3js.org/d3.v3.min.js