d3 rect with customizable rounded corners

var data = [0,1,2,3,4,5];
 var margin = {top: 10, left: 0, bottom: 10, right: 0};
var height = 200;
var width = 500;

var xScale = d3.scale.linear();
var yScale = d3.scale.linear();

var borderRadiusX = 20;

var borderRadiusY = (20);


xScale.domain([0, data.length]).range([0, width]);
yScale.domain([0, d3.max(data)]).range([0, height - margin.top - margin.bottom]);
    

var o = d3.scale.ordinal().domain(data).rangeBands([50, width]);
o.rangeBand();
o.range();
o.rangeExtent();

var barGroup = g.selectAll('.bars') 
   .data(data)
   .enter()
    .append("g");

    barGroup.append("path").attr("d", roundedRect(0, 0, 20, 40, 5	, true, true, false, false))
     
    
const roundedRect = (
  xCoord,
  yCoord,
  width,
  height,
  radius,
  needRoundingTopLeft,
  needRoundingTopRight,
  needRoundingBottomLeft,
  needRoundingBottomRight
) => {
  let retval;
  retval = 'M' + (xCoord + radius) + ',' + yCoord;
  retval += 'h' + (width - 2 * radius);

  if (needRoundingTopRight) {
    retval += 'a' + radius + ',' + radius + ' 0 0 1 ' + radius + ',' + radius;
  } else { retval += 'h' + radius; retval += 'v' + radius; }

  retval += 'v' + (height - 2 * radius);

  if (needRoundingBottomRight) {
    retval += 'a' + radius + ',' + radius + ' 0 0 1 ' + -radius + ',' + radius;
  } else { retval += 'v' + radius; retval += 'h' + -radius; }

  retval += 'h' + (2 * radius - width);

  if (needRoundingBottomLeft) {
    retval += 'a' + radius + ',' + radius + ' 0 0 1 ' + -radius + ',' + -radius;
  } else { retval += 'h' + -radius; retval += 'v' + -radius; }

  retval += 'v' + (2 * radius - height);

  if (needRoundingTopLeft) {
    retval += 'a' + radius + ',' + radius + ' 0 0 1 ' + radius + ',' + -radius;
  } else { retval += 'v' + -radius; retval += 'h' + radius; }

  retval += 'z';

  return retval;
};