Pen Settings

HTML

CSS

CSS Base

Vendor Prefixing

Add External Stylesheets/Pens

Any URLs added here will be added as <link>s in order, and before the CSS in the editor. You can use the CSS from another Pen by using its URL and the proper URL extension.

+ add another resource

JavaScript

Babel includes JSX processing.

Add External Scripts/Pens

Any URL's added here will be added as <script>s in order, and run before the JavaScript in the editor. You can use the URL of any other Pen and it will include the JavaScript from that Pen.

+ add another resource

Packages

Add Packages

Search for and use JavaScript packages from npm here. By selecting a package, an import statement will be added to the top of the JavaScript editor for this package.

Behavior

Save Automatically?

If active, Pens will autosave every 30 seconds after being saved once.

Auto-Updating Preview

If enabled, the preview panel updates automatically as you code. If disabled, use the "Run" button to update.

Format on Save

If enabled, your code will be formatted when you actively save your Pen. Note: your code becomes un-folded during formatting.

Editor Settings

Code Indentation

Want to change your Syntax Highlighting theme, Fonts and more?

Visit your global Editor Settings.

HTML

              
                <!-- adapted from https://bl.ocks.org/mbostock/4699541 -->

<svg viewBox="0 0 960 600">
  <rect width="100%" height="100%" class="background"></rect>
  <g></g>
</svg>

<div>click on a state</div>

<script src="https://d3js.org/d3.v5.min.js"></script>
<script src="https://unpkg.com/[email protected]/dist/topojson-client.min.js"></script>
              
            
!

CSS

              
                body {
  margin: 0;
  padding: 0;
  font-family: sans-serif;
  text-align: center;
  font-size: 0.9em;
  overflow: hidden;
}

svg {
  max-width: 960px;
  max-height: 90vh;
  stroke-linejoin: round;
  stroke-linecap: round;
}

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

path.feature {
  stroke-width: 0.75px;
  stroke: #fff;
  fill: #a6bddb;
  cursor: pointer;
}

              
            
!

JS

              
                // adapted from https://bl.ocks.org/mbostock/4699541

var svg = d3.select("svg");

// lookup svg width and height from DOM instead of hard-coding values
var svgWidth = +svg.attr("viewBox").split(" ")[2],
  svgHeight = +svg.attr("viewBox").split(" ")[3];

// get reference to the <rect> node, which is invisible and in the background
// wire up a click listener so that the brought up feature can be "reset" later
var rect = svg.select("rect.background").on("click", reset);

// get reference to the <g> node
// geojson features will be drawn here
var g = svg.select("g");

// the D3 geographic path generator is used for drawing the svg paths of geojson
// and during bounding box calculations
var geoPathGenerator = d3.geoPath();

// transition-related vars
var activeFeature = d3.select(null),
  transitionDuration = 1250,
  featureStrokeWidth = 0.75,
  featureStroke = "#fff",
  featureFill = "#a6bddb",
  // during transition:
  //  - swap stroke and fill colors
  //  - change stroke width
  broughtUpFeatureStrokeWidth = 3,
  broughtUpFeatureStroke = "#a6bddb",
  broughtUpFeatureFill = "#fff";

// load and draw US states topojson
d3
  .json("https://unpkg.com/[email protected]/us/10m.json")
  .then(function(loadedTopoJson) {
    var allStatesGeoJsonData = topojson.feature(
      loadedTopoJson,
      loadedTopoJson.objects.states
    );

    g
      .selectAll("path")
      .data(allStatesGeoJsonData.features)
      .enter()
      .append("path")
      .attr("d", geoPathGenerator)
      .attr("class", "feature")
      .on("click", bringUpFeature);
  });

function bringUpFeature(geoJsonDatum) {
  if (activeFeature.node() === this) {
    return reset();
  }

  activeFeature.classed("active-feature", false);

  activeFeature = d3
    .select(this)
    .classed("active-feature", true)
    .raise();

  var t = getGeoBoundsTransform(
    geoJsonDatum,
    geoPathGenerator,
    svgWidth,
    svgHeight
  );

  console.log(t);

  activeFeature
    .transition()
    .duration(transitionDuration)
    .style("stroke-width", broughtUpFeatureStrokeWidth / t.scale + "px")
    .style("stroke", broughtUpFeatureStroke)
    .style("fill", broughtUpFeatureFill)
    .attr("transform", "translate(" + t.translate + ") scale(" + t.scale + ")");

  var otherFeatures = g.selectAll("path.feature:not(.active-feature)");

  // remove the original click listener before transitioning the other features out of view
  otherFeatures.on("click", null);

  otherFeatures
    .transition()
    .duration(transitionDuration)
    .style("opacity", "0")
    .on("end", function(d, idx, nodeList) {
      // completely remove the display of the other features after transition is over
      if (idx === nodeList.length - 1) {
        otherFeatures.style("display", "none");
      }
    });
}

function reset() {
  activeFeature
    .transition()
    .duration(transitionDuration)
    .style("stroke-width", featureStrokeWidth)
    .style("stroke", featureStroke)
    .style("fill", featureFill)
    .attr("transform", "");

  var otherFeatures = g.selectAll("path.feature:not(.active-feature)");

  // reset display of other features before transitioning back into view
  otherFeatures.style("display", "");

  otherFeatures
    .transition()
    .duration(transitionDuration)
    .style("opacity", "1")
    .on("end", function(d, idx, nodeList) {
      // reestablish the original click listener after transition is over
      if (idx === nodeList.length - 1) {
        otherFeatures.on("click", bringUpFeature);
      }
    });

  activeFeature.classed("active-feature", false);
  activeFeature = d3.select(null);
}

function getGeoBoundsTransform(geoJsonDatum, geoPathGenerator, width, height) {
  var bounds = geoPathGenerator.bounds(geoJsonDatum),
    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 = 0.9 / Math.max(dx / width, dy / height),
    translate = [width / 2 - scale * x, height / 2 - scale * y];

  return {
    translate: translate,
    scale: scale
  };
}

              
            
!
999px

Console