Stacked Negative Values

A diverging stacked bar chart, with negative values descending below the x-axis.

<!DOCTYPE html>
<meta charset="utf-8">
<svg width="960" height="500"></svg>
<script src="https://d3js.org/d3.v4.min.js"></script>
<script>

var data = [
  {month: "Q1-2016", apples: 3840, bananas: 1920, cherries: -1960, dates: -400},
  {month: "Q2-2016", apples: 1600, bananas: 1440, cherries: -960, dates: -400},
  {month: "Q3-2016", apples:  640, bananas:  960, cherries: -640, dates: -600},
  {month: "Q4-2016", apples:  320, bananas:  480, cherries: -640, dates: -400}
];

var series = d3.stack()
    .keys(["apples", "bananas", "cherries", "dates"])
    .offset(d3.stackOffsetDiverging)
    (data);

var svg = d3.select("svg"),
    margin = {top: 20, right: 30, bottom: 30, left: 60},
    width = +svg.attr("width"),
    height = +svg.attr("height");

var x = d3.scaleBand()
    .domain(data.map(function(d) { return d.month; }))
    .rangeRound([margin.left, width - margin.right])
    .padding(0.1);

var y = d3.scaleLinear()
    .domain([d3.min(series, stackMin), d3.max(series, stackMax)])
    .rangeRound([height - margin.bottom, margin.top]);

var z = d3.scaleOrdinal(d3.schemeCategory10);

svg.append("g")
  .selectAll("g")
  .data(series)
  .enter().append("g")
    .attr("fill", function(d) { return z(d.key); })
  .selectAll("rect")
  .data(function(d) { return d; })
  .enter().append("rect")
    .attr("width", x.bandwidth)
    .attr("x", function(d) { return x(d.data.month); })
    .attr("y", function(d) { return y(d[1]); })
    .attr("height", function(d) { return y(d[0]) - y(d[1]); })

svg.append("g")
    .attr("transform", "translate(0," + y(0) + ")")
    .call(d3.axisBottom(x));

svg.append("g")
    .attr("transform", "translate(" + margin.left + ",0)")
    .call(d3.axisLeft(y));

function stackMin(serie) {
  return d3.min(serie, function(d) { return d[0]; });
}

function stackMax(serie) {
  return d3.max(serie, function(d) { return d[1]; });
}

</script>

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