stacked bar experiment

forked from areologist's block: axes and margins

forked from areologist's block: axes and margins - responsive

forked from areologist's block: column chart

<!DOCTYPE html>
<head>
  <meta charset="utf-8">
  <script src="https://d3js.org/d3.v4.min.js"></script>
  <script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.4/lodash.min.js"></script>
  <style>
    body { margin:0;position:fixed;top:0;right:0;bottom:0;left:0; }
    .chart {
      background-color: #f6fafc;
      border: 1px solid #333;
    }
    .bar {
      opacity: 0.7;
    }
    .bar:hover {
      opacity: 1;
    }
    .tick text {
      font-size: 10px;
    }
  </style>
</head>
<body>
  <div class="chart"></div>

const studentsBySubject = [
      {count: 63, subject: 'mathematics', group: 'freshman'},
      {count: 19, subject: 'mathematics', group: 'sophomore'},
      {count: 45, subject: 'mathematics', group: 'junior'},
      {count: 94, subject: 'mathematics', group: 'senior'},
      {count: 82, subject: 'geography', group: 'freshman'},
      {count: 8, subject: 'geography', group: 'sophomore'},
      {count: 46, subject: 'geography', group: 'junior'},
      {count: 60, subject: 'geography', group: 'senior'},
      {count: 74, subject: 'spelling', group: 'freshman'},
      {count: 74, subject: 'spelling', group: 'sophomore'},
      {count: 74, subject: 'spelling', group: 'junior'},
      {count: 74, subject: 'spelling', group: 'senior'},
      {count: 97, subject: 'reading', group: 'freshman'},
      {count: 12, subject: 'reading', group: 'sophomore'},
      {count: 34, subject: 'reading', group: 'junior'},
      {count: 17, subject: 'reading', group: 'senior'},
      {count: 52, subject: 'science', group: 'freshman'},
      {count: 52, subject: 'science', group: 'sophomore'},
      {count: 52, subject: 'science', group: 'junior'},
      {count: 52, subject: 'science', group: 'senior'}
    ];

const colors = ['#333', '#666', '#999', '#ccc'];
    const groupCount = 4;

const data = studentsBySubject;
    const subjects = _.groupBy(data, 'subject');

const svg = d3.select('.chart')
      .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 + ')');
    
    const xScale = d3.scaleBand()
    	.padding(0.2)
    	.domain(data.map(d => d.subject))
    	.range([0, width]);

const yMax = Math
    	.max(...Object
      	.values(subjects)
				.map(m => m.map(x => x.count)
        	.reduce((acc, x) => acc + x, 0)
        )
      );

const yScale = d3.scaleLinear()
    	.domain([0, yMax])
    	.range([height, 0]);

const yAxis = d3.axisLeft(yScale)
    	.ticks(10);

svg.append('g')
      .call(yAxis);

const xAxis = d3.axisBottom(xScale);

svg.append('g')
    	.attr('transform', `translate(0, ${height})`)
      .call(xAxis)
    	.selectAll('text')
    	.style('text-anchor', 'end')
    	.attr('transform', 'rotate(-45)');

const bars = svg.selectAll('.bar')
    	.data(data)
    	.enter()
    	.append('g')
    	.attr('class', 'bar');

const segmentY = (d, i, nodes) =>
    	i % groupCount === 0 ?
      yScale(d.count) :
      yScale(d.count) - (height - parseFloat(
        nodes[i-1].attributes.y.value));

bars
    	.append('rect')
      .attr('x', d => xScale(d.subject))
      .attr('y', segmentY)
      .attr('width', xScale.bandwidth())
      .attr('height', d => height - yScale(d.count))
      .attr('class', 'segment')
      .attr('fill', (d, i) => colors[i % 4]);
  </script>
</body>

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

https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.4/lodash.min.js