D3 Examples - d3fc extent example

d3fc extent example

This is a simple demonstration of the d3fc extent component, which provides a flexible mechanism for computing the domain of a chart. It allows you to add padding, define multiple accessors, include fixed values (e.g. ensure it includes zero), etc.

var yExtent = fc.extentLinear() // the property of the data that defines the y extent .accessors([function(d) { return d.close; }]) // pad by 10% in the +ve direction .pad([0, 0.1]) // ensure that the extent includes zero .include([0]); var xExtent = fc.extentDate() // the property of the data that defines the x extent .accessors([function(d) { return d.date; }]) // pad in domain units (in this case milliseconds) .padUnit('domain') // ensure that the scale is padded by one day in either direction .pad([millisPerDay, millisPerDay]); // apply the extent to the scales x.domain(xExtent(data)); y.domain(yExtent(data));

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<!DOCTYPE html>
<!-- include polyfills for custom event, Symbol and Custom Elements -->
<script src="//unpkg.com/babel-polyfill@6.26.0/dist/polyfill.js"></script>
<script src="//unpkg.com/custom-event-polyfill@0.3.0/custom-event-polyfill.js"></script>
<script src="//cdnjs.cloudflare.com/ajax/libs/document-register-element/1.8.0/document-register-element.js"></script>
​
<!-- use babel so that we can use arrow functions and other goodness in this block! -->
<script src="//unpkg.com/babel-standalone@6/babel.min.js"></script>
​
<script src="//unpkg.com/d3@5.5.0"></script>
<script src="//unpkg.com/d3fc@14.0.1"></script>
​
<style> /* set the CSS */
​
.line {
  fill: none;
  stroke: steelblue;
  stroke-width: 2px;
}
​
</style>
<body>
​
<script>
​
// set the dimensions and margins of the graph
var margin = {top: 20, right: 20, bottom: 30, left: 50},
    width = 960 - margin.left - margin.right,
    height = 500 - margin.top - margin.bottom;
​
// parse the date / time
var parseTime = d3.timeParse("%d-%b-%y");
​
// set the ranges
var x = d3.scaleTime().range([0, width]);
var y = d3.scaleLinear().range([height, 0]);
​
// define the line
var valueline = d3.line()
    .x(function(d) { return x(d.date); })
    .y(function(d) { return y(d.close); });
​
// append the svg obgect to the body of the page
// appends a 'group' element to 'svg'
// moves the 'group' element to the top left margin
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 + ")");
​
// Get the data
d3.csv("data.csv").then(data => {
​
  // format the data
  data.forEach(function(d) {
      d.date = parseTime(d.date);
      d.close = +d.close;
  });
  
  var millisPerDay = 1000 * 60 * 60 * 24;
  
  var yExtent = fc.extentLinear()
    .accessors([function(d) { return d.close; }])
    .pad([0, 0.1])
    .include([0]);
  
  var xExtent = fc.extentDate()
    .accessors([function(d) { return d.date; }])
    .padUnit('domain')
    .pad([millisPerDay, millisPerDay]);
​
  // scale the range of the data
  x.domain(xExtent(data));
  y.domain(yExtent(data));
​
  // add the valueline path.
  svg.append("path")
     .data([data])
     .attr("class", "line")
     .attr("d", valueline);
​
  // add the dots
  svg.selectAll("dot")
     .data(data)
     .enter().append("circle")
       .attr("r", 5)
       .attr("cx", function(d) { return x(d.date); })
       .attr("cy", function(d) { return y(d.close); });
​
  // add the X Axis
  svg.append("g")
      .attr("transform", "translate(0," + height + ")")
      .call(d3.axisBottom(x));
​
  // add the Y Axis
  svg.append("g")
      .call(d3.axisLeft(y));
​
});
​
</script>
</body>
​
    