Reusable D3 Tooltip

This is my first attempt at a reusable function for creating tooltips on D3 charts.

<!DOCTYPE html>
<meta charset="utf-8">
  <head>
   	<link href='https://fonts.googleapis.com/css?family=Play' rel='stylesheet' type='text/css'>
<style>

body {
	margin:auto;
	font-family: 'Play', sans-serif;
}

text {
    font-family: 'Play', sans-serif;
}

</style>

// Dummy Data for the chart

var data = [
    {name:'A',count:64,description:"This is column A!"},
    {name:'B',count:32,description:"This is column B!"},
    {name:'C',count:16,description:"This is column C!"},
    {name:'D',count:8,description:"This is column D!"},
    {name:'E',count:4,description:"This is column E!"},
    {name:'F',count:2,description:"This is column F!"},
];

// Draw a basic bar chart

var margin = {top:20, left:50, bottom:50, right:20};
var height = 500 - margin.top - margin.bottom,
    width = 960 - margin.left - margin.right;

var svg = d3.select("body")
        .append("svg")
        .attr("height", height + margin.top + margin.bottom)
        .attr("width", width + margin.left + margin.right)
        .style("cursor","default")
        .append("g")
        .attr("transform","translate(" + margin.left + "," + margin.top + ")");

var x = d3.scaleBand() 
    .domain(data.map(function(d) { return d.name;}))
    .range([0,width])
    .padding(.1);

var y = d3.scaleLinear()
    .domain([0,70])
    .range([height,0]);

var color = d3.scaleOrdinal(d3.schemeCategory10)
    .domain(x.domain())

var tooltip = d3.tooltip() // returns the tooltip function
    .extent([[0,0],[width,height]]) // tells the tooltip how much area it has to work with
    .tips(["name","description"],["Bar Name: ","Description: "]) // tells the tooltip which properties to display in the tip and what to label thme
    .fontSize(12) // sets the font size for the tooltip
    .padding([8,4]) // sets the amount of padding in the tooltip rectangle
    .margin([10,10]); // set the distance H and V to keep the tooltip from the mouse pointer

svg.selectAll(".bar")
    .data(data)
    .enter()
    .append("rect")
    .attr("x", function(d) { return x(d.name)})
    .attr("y", function(d) { return y(d.count)})
    .attr("width", x.bandwidth())
    .attr("height", function(d) { return height - y(d.count)})
    .attr("fill", function(d) { return color(d.name)})
    .each(tooltip.events); // attaches the tooltips mouseenter/leave/move events but does not overwrite previously attached events

svg.append("g")
    .attr("transform", "translate(0," + height + ")")
    .call(d3.axisBottom(x))

svg.append("g")
    .call(d3.axisLeft(y));

svg.call(tooltip) // draws the tooltip;

</script>

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