Zoom to Bounding Box II - Updated for d3 v4

Updated variant of Zoom to Bounding Box II for d3 v4 which is also a variant of the Zoom to Bounding Box example that uses zoom transitions to smoothly interpolate between different views. This example also allows you to freely pan and zoom with the mouse (or touch).

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

.background {
  fill: none;
  pointer-events: all;
}

.feature {
  fill: #ccc;
  cursor: pointer;
}

.feature.active {
  fill: orange;
}

.mesh {
  fill: none;
  stroke: #fff;
  stroke-linecap: round;
  stroke-linejoin: round;
}

</style>
<body>
<script src="https://d3js.org/d3.v4.min.js"></script> 
<script src="https://d3js.org/topojson.v1.min.js"></script>
<script>

var width = 960,
    height = 500,
    active = d3.select(null);

var projection = d3.geoAlbersUsa() // updated for d3 v4
    .scale(1000)
    .translate([width / 2, height / 2]);

var zoom = d3.zoom()
    // no longer in d3 v4 - zoom initialises with zoomIdentity, so it's already at origin
    // .translate([0, 0]) 
    // .scale(1) 
    .scaleExtent([1, 8])
    .on("zoom", zoomed);

var path = d3.geoPath() // updated for d3 v4
    .projection(projection);

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

svg.append("rect")
    .attr("class", "background")
    .attr("width", width)
    .attr("height", height)
    .on("click", reset);

var g = svg.append("g");

svg
    .call(zoom); // delete this line to disable free zooming
    // .call(zoom.event); // not in d3 v4

d3.json("/../../data/us.json", function(error, us) {
  if (error) throw error;

g.selectAll("path")
      .data(topojson.feature(us, us.objects.states).features)
    .enter().append("path")
      .attr("d", path)
      .attr("class", "feature")
      .on("click", clicked);

g.append("path")
      .datum(topojson.mesh(us, us.objects.states, function(a, b) { return a !== b; }))
      .attr("class", "mesh")
      .attr("d", path);
});

function clicked(d) {
  if (active.node() === this) return reset();
  active.classed("active", false);
  active = d3.select(this).classed("active", true);

var bounds = path.bounds(d),
      dx = bounds[1][0] - bounds[0][0],
      dy = bounds[1][1] - bounds[0][1],
      x = (bounds[0][0] + bounds[1][0]) / 2,
      y = (bounds[0][1] + bounds[1][1]) / 2,
      scale = Math.max(1, Math.min(8, 0.9 / Math.max(dx / width, dy / height))),
      translate = [width / 2 - scale * x, height / 2 - scale * y];

svg.transition()
      .duration(750)
      // .call(zoom.translate(translate).scale(scale).event); // not in d3 v4
      .call( zoom.transform, d3.zoomIdentity.translate(translate[0],translate[1]).scale(scale) ); // updated for d3 v4
}

function reset() {
  active.classed("active", false);
  active = d3.select(null);

svg.transition()
      .duration(750)
      // .call( zoom.transform, d3.zoomIdentity.translate(0, 0).scale(1) ); // not in d3 v4
      .call( zoom.transform, d3.zoomIdentity ); // updated for d3 v4
}

function zoomed() {
  g.style("stroke-width", 1.5 / d3.event.transform.k + "px");
  // g.attr("transform", "translate(" + d3.event.translate + ")scale(" + d3.event.scale + ")"); // not in d3 v4
  g.attr("transform", d3.event.transform); // updated for d3 v4
}

// If the drag behavior prevents the default click,
// also stop propagation so we don’t click-to-zoom.
function stopped() {
  if (d3.event.defaultPrevented) d3.event.stopPropagation();
}

</script>

Changed /mbostock/raw/4090846/us.json to a local referenece

https://d3js.org/d3.v4.min.js

https://d3js.org/topojson.v1.min.js