progress bar using scale

<!DOCTYPE html>

<head>
  <meta charset="utf-8">
  <script src="https://d3js.org/d3.v4.min.js"></script>
  <style>
    body {
      margin: 10;
      padding: 10;
      position: fixed;
      top: 0;
      right: 0;
      bottom: 0;
      left: 0;
    }

svg {
      margin: 10;
      padding: 10
    }

path {
      display: none;
    }
  </style>
</head>

<body>
  <script>
    // visits is the website speed where we want the tracker to be
    var visits = 26,
      chunks = [3, 5, 8, 20, 24],
      ticks = [0, 3, 5, 8, 20, 30],
      tickLabels = ['0', '3s', '5s', '8s', '20s', '30s'],
      width = 500,
      height = 80
    var margin = {
      top: 0,
      bottom: 0,
      left: 20,
      right: 0
    };

// Feel free to change or delete any of the code you see in this editor!
    var svg = d3.select("body").append("svg")
      .attr("width", width)
      .attr("height", 500);

var threshold = d3.scaleThreshold()
      .domain([3, 5, 8, 30])
      .range(["#009654", "#00d48a", "#ffa171", "#fd4a49", ]);

var x = d3.scaleLinear().range([10, width - margin.left]).domain([0, 30]);

var xAxis = d3.axisBottom()
      .scale(x);

svg.append("g")
      .attr("class", "x axis")
      .attr("transform", "translate(0," + height + ")")
      .call(xAxis
        .ticks(5)
        .tickValues(ticks)
        .tickFormat(function (d, i) {
          return tickLabels[i]
        }))
      .append("text")
      .attr("class", "label")
      .attr("transform", "translate(" + width + ",0)")
      .attr("y", -5)

svg.selectAll("rect")
      .data(threshold.range().map(function (color) {
        var d = threshold.invertExtent(color);
        if (d[0] == null) d[0] = x.domain()[0];
        if (d[1] == null) d[1] = x.domain()[1];
        return d;
      }))
      .enter().append("rect")
      .attr("height", 60)
      .attr("x", function (d) {
        return x(d[0]);
      })
      .attr("y", height - 60)
      .attr("width", function (d) {
        return x(d[1]) - x(d[0]);
      })
      .attr("fill", function (d) {
        return threshold(d[0]);
      });

svg.append('g')
      .append('text')
      .attr('font-family', 'FontAwesome')
      .attr("dx", x(visits))
      .attr("dy", height - 60)
      .attr('font-size', function (d) {
        return 24 + 'px'
      })
      .text(function (d) {
        return '\u2713' // this is unicode of the font awesome icon
      });
  </script>
</body>

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