Transition hacking with chains

Similar to this transition hacking example, this turns an asynchronous d3 transition into something that can be paused/fast-forwarded/rewound while still using the nice syntax, easing, interpolation, etc. of d3.transition.

This version respects chained transitions and delays by expecting an absolute time value in milliseconds rather than a relative time value between 0 and 1.

Caveat #1: This doesn't yet work if you have multiple transitions in a chain modifying the same property.

Caveat #2: this is probably a pretty bad idea! Maybe it can be done by tinkering directly with the internal timer instead?

<!DOCTYPE html>
<meta charset="utf-8">
<style>

body {
    text-align: center;
    font: 16px sans-serif;
  }

button {
    margin: 0 0.5em;
  }

circle {
    stroke: #000;
    stroke-width: 1.5px;
  }

</style>
<body>
<script src="//cdnjs.cloudflare.com/ajax/libs/d3/3.5.14/d3.min.js"></script>
<script src="d3-record.js"></script>
<script>

var margin = {top: 100, right: 100, bottom: 100, left: 100},
    width = 960 - margin.left - margin.right,
    height = 440 - margin.top - margin.bottom;

var x = d3.scale.ordinal()
    .domain(d3.range(5))
    .rangePoints([0, width]);

var y = x.copy()
    .rangePoints([0, height]);

var color = d3.scale.linear()
    .domain(d3.extent(x.domain()))
    .range(["hsl(297,50%,47%)", "hsl(81,78%,61%)"])
    .interpolate(d3.interpolateHcl);

var svg = d3.select("body").append("svg")
  .attr("width", width + margin.left + margin.right)
  .attr("height", height + margin.top + margin.bottom)
  .append("g")
    .attr("transform", "translate(" + margin.left + "," + margin.top + ")");

var dots = svg.selectAll("circle")
  .data(x.domain())
  .enter()
  .append("circle")
    .attr("r",20)
    .attr("cx",0)
    .attr("cy",y)
    .style("fill",color);

// Declare a normal transition
dots.transition()
  .duration(2500)
  .delay(function(d){
    return d * 100;
  })
  .attr("cx",x)
  .transition()
    .attr("r",40)
    .filter(function(d){
      return d % 2;
    })
    .transition()
      .style("opacity",0);

// "Record" the transition into a function that can jump to any time
// `true` means it expects an absolute time in ms
var jumpToTime = dots.record(true);

d3.select("body").append("div")
  .text("Jump to: ")
  .selectAll("button")
  .data(d3.range(0,8500,1000))
  .enter()
  .append("button")
    .text(function(d){
      return Math.round(d/1000) + " sec";
    })
    .on("click",jumpToTime);

</script>

https://cdnjs.cloudflare.com/ajax/libs/d3/3.5.14/d3.min.js