Scatterplot with tooltip

<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width">
    <script src="https://d3js.org/d3.v4.min.js"></script>
    <script src="https://unpkg.com/d3-tip@0.7.1"></script>
    <script src="https://cdnjs.cloudflare.com/ajax/libs/d3-legend/2.24.0/d3-legend.min.js"></script>
    <title>Basic Scatter Plot</title>
    <style>
      body {
        margin: 0px;
      }
      .domain {
        display: none;
      }
      .tick line {
        stroke: #C0C0BB;
      }
      .tick text, .legendCells text {
        fill: #8E8883;
        font-size: 18pt;
        font-family: sans-serif;
      }
      .axis-label, .legend-label {
        fill: #635F5D;
        font-size: 28pt;
        font-family: sans-serif;
      }
   		/* Tooltip styles copied from
    		https://bl.ocks.org/Caged/6476579 */
      .d3-tip {
        line-height: 1;
        padding: 12px;
        background: rgba(0, 0, 0, 0.8);
        color: #fff;
        border-radius: 2px;
      }
    </style>
  </head>
  <body>
    <svg width="960" height="500"></svg>
    <script>
      const xValue = d => d.sepalLength;
      const xLabel = 'Sepal Length';
      const yValue = d => d.petalLength;
      const yLabel = 'Petal Length';
      const colorValue = d => d.species;
      const colorLabel = 'Species';
      const margin = { left: 120, right: 300, top: 20, bottom: 120 };

const svg = d3.select('svg');
      const width = svg.attr('width');
      const height = svg.attr('height');
      const innerWidth = width - margin.left - margin.right;
      const innerHeight = height - margin.top - margin.bottom;

xAxisG.append('text')
          .attr('class', 'axis-label')
          .attr('x', innerWidth / 2)
          .attr('y', 100)
          .text(xLabel);

yAxisG.append('text')
          .attr('class', 'axis-label')
          .attr('x', -innerHeight / 2)
          .attr('y', -60)
          .attr('transform', `rotate(-90)`)
          .style('text-anchor', 'middle')
          .text(yLabel);

colorLegendG.append('text')
          .attr('class', 'legend-label')
          .attr('x', -30)
          .attr('y', -40)
          .text(colorLabel);

const xScale = d3.scaleLinear();
      const yScale = d3.scaleLinear();
      const colorScale = d3.scaleOrdinal()
        .range(d3.schemeCategory10);

const xAxis = d3.axisBottom()
        .scale(xScale)
        .tickPadding(15)
        .tickSize(-innerHeight);

const yAxis = d3.axisLeft()
        .scale(yScale)
        .ticks(5)
        .tickPadding(15)
        .tickSize(-innerWidth);

const colorLegend = d3.legendColor()
        .scale(colorScale)
        .shape('circle');

yScale
          .domain(d3.extent(data, yValue))
          .range([innerHeight, 0])
          .nice();

g.selectAll('circle').data(data)
          .enter().append('circle')
            .attr('cx', d => xScale(xValue(d)))
            .attr('cy', d => yScale(yValue(d)))
            .attr('fill', d => colorScale(colorValue(d)))
            .attr('fill-opacity', 0.6)
            .attr('r', 8)
           	.on('mouseover', tip.show)
      			.on('mouseout', tip.hide)

xAxisG.call(xAxis);
        yAxisG.call(yAxis);
        colorLegendG.call(colorLegend)
          .selectAll('.cell text')
            .attr('dy', '0.1em');
      });
    </script>
  </body>
</html>

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

https://unpkg.com/d3-tip@0.7.1

https://cdnjs.cloudflare.com/ajax/libs/d3-legend/2.24.0/d3-legend.min.js