Simple bar graph in v4

This is a simple bar graph written using d3.js v4.

This graph is part of the code samples for the update to the book D3 Tips and Tricks to version 4 of d3.js.

<!DOCTYPE html>
<meta charset="utf-8">
<style> /* set the CSS */

.bar { fill: steelblue; }

</style>
<body>
	
    	
<script src="https://d3js.org/d3.v4.min.js"></script>
<script>

// set the dimensions and margins of the graph
var margin = {top: 20, right: 20, bottom: 30, left: 40},
    width = 960 - margin.left - margin.right,
    height = 500 - margin.top - margin.bottom;

// set the ranges
var x = d3.scaleBand()
          .range([0, width])
          .padding(0.1);
var y = d3.scaleLinear()
          .range([height, 0]);
          
// append the svg object to the body of the page
// append 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("sales.csv", function(error, data) {
  if (error) throw error;

// format the data
  data.forEach(function(d) {
    d.sales = +d.sales;
  });

// Scale the range of the data in the domains
  x.domain(data.map(function(d) { return d.salesperson; }));
  y.domain([0, d3.max(data, function(d) { return d.sales; })]);

// append the rectangles for the bar chart
  svg.selectAll(".bar")
      .data(data)
    .enter().append("rect")
      .attr("class", "bar")
      .attr("x", function(d) { return x(d.salesperson); })
      .attr("width", x.bandwidth())
      .attr("y", function(d) { return y(d.sales); })
      .attr("height", function(d) { return height - y(d.sales); });

// 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>

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