Grouped/Stacked Bar Chart

<!DOCTYPE html>
<head>
  <meta charset="utf-8">
  <script src="https://d3js.org/d3.v4.min.js"></script>
  <style>
    .axis .domain {
      display: none;
    }
    form {
      position: absolute;
      right: 10px;
      top: 10px;
    }
  </style>
</head>

<body>
  <form>
    <label><input type="radio" name="mode" value="grouped" checked> Grouped</label>
    <label><input type="radio" name="mode" value="stacked"> Stacked</label>
  </form>
  <svg width="960" height="500"></svg>
  <script>

var svg = d3.select("svg"),
    margin = {top: 20, right: 20, bottom: 30, left: 40},
    width = +svg.attr("width") - margin.left - margin.right,
    height = +svg.attr("height") - margin.top - margin.bottom,
    g = svg.append("g").attr("transform", "translate(" + margin.left + "," + margin.top + ")");

var x0 = d3.scaleBand()
  .rangeRound([0, width])
  .paddingInner(0.05);

var x1 = d3.scaleBand()
  .padding(0.05);

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

var z = d3.scaleOrdinal()
  .range(["#98abc5", "#a05d56", "#d0743c", "#ff8c00"]);

d3.csv('stocks.csv', (error, data) => {

if (error) throw error;

// Nest stock values by symbol.
    var dataByYear = d3.nest()
        .key(d => { return d.date.split(" ")[1]; })
        .key(d => { return d.symbol; })
        .rollup(v => {
          return d3.sum(v, d => { return d.price; });
        })
        .entries(data);

dataByYear.forEach( y => {

y.year = y.key;
      delete y.key;

y.values.forEach(d => {
        d.symbol = d.key;
        d.sum_price = +d.value;
        delete d.key;
        delete d.value;
      });

y.values.sort( (a, b) => {
        return b.sum_price - a.sum_price;
      });

});

let symbolList = dataByYear[0].values.map(d => { return d.symbol; });
    let yearList = dataByYear.map(d => { return d.year; });

x0.domain(yearList);
    x1.domain(symbolList).rangeRound([0, x0.bandwidth()]);
    y.domain([0, d3.max(dataByYear, d => {return d3.max(d.values, el => { return el.sum_price; }); })]).nice();
    z.domain(symbolList);

var year = g.append("g")
    .selectAll("g")
    .data(dataByYear)
    .enter().append("g")
    .attr("transform", d => { return "translate(" + x0(d.year) + ",0)"; })

var rect = year.selectAll("rect")
    .data( d => { return d.values; })
    .enter().append("rect")
    .attr("y", height)
    .attr("width", x0.bandwidth())
    .attr("height", 0);

let drawAxis = () => {
      g.append("g")
      .attr("class", "axis")
      .attr("transform", "translate(0," + height + ")")
      .call(d3.axisBottom(x0));

g.append("g")
      .attr("class", "axis")
      .call(d3.axisLeft(y).ticks(null, "s"))
      .append("text")
      .attr("x", 2)
      .attr("y", y(y.ticks().pop()) + 0.5)
      .attr("dy", "0.32em")
      .attr("fill", "#000")
      .attr("font-weight", "bold")
      .attr("text-anchor", "start")
      .text("Price");
    }

let drawLegend = (data) => {
      var legend = g.append("g")
      .attr("font-family", "sans-serif")
      .attr("font-size", 10)
      .attr("text-anchor", "end")
      .selectAll("g")
      .data(data)
      .enter().append("g")
      .attr("transform", (d, i) => { return "translate(0," + i * 20 + ")"; });

legend.append("rect")
      .attr("x", width - 19)
      .attr("width", 19)
      .attr("height", 19)
      .attr("fill", z);

legend.append("text")
      .attr("x", width - 24)
      .attr("y", 9.5)
      .attr("dy", "0.32em")
      .text( d => { return d; });
    }

drawGroupedBars();
    drawAxis();
    drawLegend(symbolList);

d3.selectAll("input").on("change", change);

var timeout = setTimeout( () => {
      d3.select("input[value=\"grouped\"]").property("checked", true).each(change);
    }, 2000);

function change() {
      clearTimeout(timeout);
      if (this.value === "grouped") transitionGrouped();
      else transitionStacked();
    }

function transitionGrouped() {

rect.transition()
      .duration(500)
      .delay( (d, i) => { return i * 10; })
      .attr("x", d => { return x1(d.symbol); })
      .attr("width", x1.bandwidth())
      .transition()
      .attr("y", d => { return y(d.sum_price); })
      .attr("height", d => { return height - y(d.sum_price); });
    }

function transitionStacked() {

rect.transition()
      .duration(500)
      .delay( (d, i) => { return i * 10; })
      .attr("y", d => { return y(d.sum_price); })
      .attr("height", d => { return height - y(d.sum_price); })
      .transition()
      .attr("x", d => { return x0(d.symbol); })
      .attr("width", x0.bandwidth());
    }

});

</script>
</body>

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