bar graph in v4 with a bar brush

forked from d3noob's block: Simple bar graph in v4

... to demonstrate how to add a brush for each bar for partial selection

<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8"/>
<script src="https://unpkg.com/d3@4.12.0/build/d3.min.js"></script>

</head>
<body style="background-color:white;">
<style>.brush .selection {fill: red; fill-opacity: 1;}</style>
<script>
    
    // bar chart code entirely from d3noob
    
    //    https://bl.ocks.org/d3noob/bdf28027e0ce70bd132edc64f1dd7ea4
    
    
    
    
    
    // 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 + ")");
    
    
    
    // make up data instead of get from csv
    
    data = [
    
    {salesperson: "A", sales: Math.random() * 100},
    
    {salesperson: "B", sales: Math.random() * 100},
    
    {salesperson: "C", sales: Math.random() * 100}
    
    ];
    
    
    
    // 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
    
    //  but use g to contain each bar
    
    var barg = svg.selectAll(".bar")
    
    .data(data)
    
    .enter().append("g")
    
    .attr("class", "bar")
    
    .attr(
    
    "transform",
    
    function(d) {
    
    return "translate(" + x(d.salesperson) + "," + 0 + ")"
    
    }
    
    )
    
    
    
    barg.append("rect")
    
    .attr("width", x.bandwidth())
    
    .attr("height", function(d) { return height - y(d.sales); })
    
    .attr("y", function(d) {return y(d.sales)})
    
    .style("fill", "#888");
    
    
    
    // now for fun add a brush on each bar
    
    var brush = d3.brushY()
    
    
    
    barg.append("g")
    
    .attr("class", "brush")
    
    .each(function(d) {
    
    d3.select(this)
    
    .call(brush.extent([[0,y(d.sales)], [x.bandwidth(), height]]))
    
    })
    
    
    
    // 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>
</html>

https://unpkg.com/d3@4.12.0/build/d3.min.js