d3js clickable stacked bar chart

Clickable legend added to Mike Bostock's stacked bar chart to select display of an individual category. With help from yuuniverse4444’s block #8325617.

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

body {
  font: 10px sans-serif;
}

.axis path,
.axis line {
  fill: none;
  stroke: #000;
  shape-rendering: crispEdges;
}

.bar {
  fill: steelblue;
}

.x.axis path {
  display: none;
}

.tooltip{
  text-anchor: middle;
  font-family: sans-serif;
  font-size: 10px;
  font-weight: bold;
  fill:black; 
}

</style>
<body>
<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/3.5.13/d3.min.js"></script>
<script>

var margin = {top: 20, right: 20, bottom: 30, left: 40},
    width = 960 - margin.left - margin.right,
    height = 500 - margin.top - margin.bottom;

var x = d3.scale.ordinal()
    .rangeRoundBands([0, width], .1);

var y = d3.scale.linear()
    .rangeRound([height, 0]);

var color = d3.scale.ordinal()
    .range(["#98abc5", "#8a89a6", "#7b6888", "#6b486b", "#a05d56", "#d0743c", "#ff8c00"]);

var xAxis = d3.svg.axis()
    .scale(x)
    .orient("bottom");

var yAxis = d3.svg.axis()
    .scale(y)
    .orient("left")
    .tickFormat(d3.format(".2s"));

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 active_link = "0"; //to control legend selections and hover
var legendClicked; //to control legend selections
var legendClassArray = []; //store legend classes to select bars in plotSingle()
var y_orig; //to store original y-posn

d3.csv("state_data.csv", function(error, data) {
  if (error) throw error;

color.domain(d3.keys(data[0]).filter(function(key) { return key !== "State"; }));

data.forEach(function(d) {
    var mystate = d.State; //add to stock code
    var y0 = 0;
    //d.ages = color.domain().map(function(name) { return {name: name, y0: y0, y1: y0 += +d[name]}; });
    d.ages = color.domain().map(function(name) { return {mystate:mystate, name: name, y0: y0, y1: y0 += +d[name]}; });
    d.total = d.ages[d.ages.length - 1].y1;

});

data.sort(function(a, b) { return b.total - a.total; });

x.domain(data.map(function(d) { return d.State; }));
  y.domain([0, d3.max(data, function(d) { return d.total; })]);

svg.append("g")
      .attr("class", "x axis")
      .attr("transform", "translate(0," + height + ")")
      .call(xAxis);

svg.append("g")
      .attr("class", "y axis")
      .call(yAxis)
    .append("text")
      .attr("transform", "rotate(-90)")
      .attr("y", 6)
      .attr("dy", ".71em")
      .style("text-anchor", "end");
      //.text("Population");

var state = svg.selectAll(".state")
      .data(data)
    .enter().append("g")
      .attr("class", "g")
      .attr("transform", function(d) { return "translate(" + "0" + ",0)"; });
      //.attr("transform", function(d) { return "translate(" + x(d.State) + ",0)"; })

state.selectAll("rect")
      .data(function(d) {
        return d.ages; 
      })
    .enter().append("rect")
      .attr("width", x.rangeBand())
      .attr("y", function(d) { return y(d.y1); })
      .attr("x",function(d) { //add to stock code
          return x(d.mystate)
        })
      .attr("height", function(d) { return y(d.y0) - y(d.y1); })
      .attr("class", function(d) {
        classLabel = d.name.replace(/\s/g, ''); //remove spaces
        return "class" + classLabel;
      })
      .style("fill", function(d) { return color(d.name); });

state.selectAll("rect")
       .on("mouseover", function(d){

var delta = d.y1 - d.y0;
          var xPos = parseFloat(d3.select(this).attr("x"));
          var yPos = parseFloat(d3.select(this).attr("y"));
          var height = parseFloat(d3.select(this).attr("height"))

d3.select(this).attr("stroke","blue").attr("stroke-width",0.8);

svg.append("text")
          .attr("x",xPos)
          .attr("y",yPos +height/2)
          .attr("class","tooltip")
          .text(d.name +": "+ delta); 
          
       })
       .on("mouseout",function(){
          svg.select(".tooltip").remove();
          d3.select(this).attr("stroke","pink").attr("stroke-width",0.2);
                                
        })

var legend = svg.selectAll(".legend")
      .data(color.domain().slice().reverse())
    .enter().append("g")
      //.attr("class", "legend")
      .attr("class", function (d) {
        legendClassArray.push(d.replace(/\s/g, '')); //remove spaces
        return "legend";
      })
      .attr("transform", function(d, i) { return "translate(0," + i * 20 + ")"; });

//reverse order to match order in which bars are stacked    
  legendClassArray = legendClassArray.reverse();

legend.append("rect")
      .attr("x", width - 18)
      .attr("width", 18)
      .attr("height", 18)
      .style("fill", color)
      .attr("id", function (d, i) {
        return "id" + d.replace(/\s/g, '');
      })
      .on("mouseover",function(){

if (active_link === "0") d3.select(this).style("cursor", "pointer");
        else {
          if (active_link.split("class").pop() === this.id.split("id").pop()) {
            d3.select(this).style("cursor", "pointer");
          } else d3.select(this).style("cursor", "auto");
        }
      })
      .on("click",function(d){

if (active_link === "0") { //nothing selected, turn on this selection
          d3.select(this)           
            .style("stroke", "black")
            .style("stroke-width", 2);

active_link = this.id.split("id").pop();
            plotSingle(this);

//gray out the others
            for (i = 0; i < legendClassArray.length; i++) {
              if (legendClassArray[i] != active_link) {
                d3.select("#id" + legendClassArray[i])
                  .style("opacity", 0.5);
              }
            }
           
        } else { //deactivate
          if (active_link === this.id.split("id").pop()) {//active square selected; turn it OFF
            d3.select(this)           
              .style("stroke", "none");

active_link = "0"; //reset

//restore remaining boxes to normal opacity
            for (i = 0; i < legendClassArray.length; i++) {              
                d3.select("#id" + legendClassArray[i])
                  .style("opacity", 1);
            }

//restore plot to original
            restorePlot(d);

}

} //end active_link check
                          
                                
      });

legend.append("text")
      .attr("x", width - 24)
      .attr("y", 9)
      .attr("dy", ".35em")
      .style("text-anchor", "end")
      .text(function(d) { return d; });

function restorePlot(d) {

state.selectAll("rect").forEach(function (d, i) {      
      //restore shifted bars to original posn
      d3.select(d[idx])
        .transition()
        .duration(1000)        
        .attr("y", y_orig[i]);
    })

//restore opacity of erased bars
    for (i = 0; i < legendClassArray.length; i++) {
      if (legendClassArray[i] != class_keep) {
        d3.selectAll(".class" + legendClassArray[i])
          .transition()
          .duration(1000)
          .delay(750)
          .style("opacity", 1);
      }
    }

}

function plotSingle(d) {
        
    class_keep = d.id.split("id").pop();
    idx = legendClassArray.indexOf(class_keep);    
   
    //erase all but selected bars by setting opacity to 0
    for (i = 0; i < legendClassArray.length; i++) {
      if (legendClassArray[i] != class_keep) {
        d3.selectAll(".class" + legendClassArray[i])
          .transition()
          .duration(1000)          
          .style("opacity", 0);
      }
    }

//lower the bars to start on x-axis
    y_orig = [];
    state.selectAll("rect").forEach(function (d, i) {        
    
      //get height and y posn of base bar and selected bar
      h_keep = d3.select(d[idx]).attr("height");
      y_keep = d3.select(d[idx]).attr("y");
      //store y_base in array to restore plot
      y_orig.push(y_keep);

h_base = d3.select(d[0]).attr("height");
      y_base = d3.select(d[0]).attr("y");

h_shift = h_keep - h_base;
      y_new = y_base - h_shift;

//reposition selected bars
      d3.select(d[idx])
        .transition()
        .ease("bounce")
        .duration(1000)
        .delay(750)
        .attr("y", y_new);
   
    })    
   
  }

});

</script>

https://cdnjs.cloudflare.com/ajax/libs/d3/3.5.13/d3.min.js