Simple Circle Pack - rsp

This is the simplest circle pack diagram I could create. Let me know if you think I can make it tighter.

Build notes:

It pulls data from a csv file. It uses d3.stratify() to reform links into a hierarchy. (NOTE: I ran into a challenge with d.size when moving from json to csv. While size is a feature of my data, I had to now access it from d.data.size.)
To differentiate between local variables and framework objects, I prefix variables with lowercase 'v'.

From https://bl.ocks.org/denjn5/6d5ddd4226506d644bb20062fc60b53f

forked from denjn5's block: Simple Circle Pack (d3 v4; CSV; 50 Lines)

<!DOCTYPE html>
<meta charset="utf-8">
<head>
    <title>Simple Circle Pack (d3 v4; CSV; 50 Lines)</title>
    <script src="https://d3js.org/d3.v4.min.js"></script>
</head>

// add viewBox and preserveAspectRatio properties,
    // and call resize so that svg resizes on inital page load
    svg.attr("viewBox", "0 0 " + width + " " + height)
        .attr("perserveAspectRatio", "xMinYMid")
        .call(resize);

// to register multiple listeners for same event type, 
    // you need to add namespace, i.e., 'click.foo'
    // necessary if you call invoke this function for multiple svgs
    // api docs: https://github.com/mbostock/d3/wiki/Selections#on
    d3.select(window).on("resize." + container.attr("id"), resize);

// get width of container and resize svg to fit it
    function resize() {
        var targetWidth = parseInt(container.style("width"));
        svg.attr("width", targetWidth);
        svg.attr("height", Math.round(targetWidth / aspect));
    }
}  
</script>

// Prepare our physical space
    var g = d3.select('svg')
    .attr('width', vWidth)
    .attr('height', vHeight)
    .call(responsivefy)
    .select('g')
//     .call(responsivefy);

// Get the data from our CSV file
    d3.csv('data.csv', function(error, vCsvData) {
        if (error) throw error;

vData = d3.stratify()(vCsvData);
        drawViz(vData);
    });

function drawViz(vData) {
        // Declare d3 layout
        var vLayout = d3.pack().size([vWidth, vHeight]);

// Layout + Data
        var vRoot = d3.hierarchy(vData).sum(function (d) { return d.data.size; });
        var vNodes = vRoot.descendants();
        vLayout(vRoot);
        var vSlices = g.selectAll('circle').data(vNodes).enter().append('circle');

// Draw on screen
        vSlices.attr('cx', function (d) { return d.x; })
            .attr('cy', function (d) { return d.y; })
            .attr('r', function (d) { return d.r; });
    }

</script>
</body>
<script>  // ------------ helper scripts ------------
    
  // fn dynamic chart resizing  (https://brendansudol.com/writing/responsive-d3)  
  function responsivefy(svg) {
    // get container + svg aspect ratio
    var container = d3.select(svg.node().parentNode),
        width = parseInt(svg.style("width")),
        height = parseInt(svg.style("height")),
        aspect = width / height;

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