Rounded Heatmap in JavaScript

// Seeded PRNG so the heatmap is identical on every load (stable snapshots).
var __seed = 0x66f70829
function rand() {
  __seed |= 0
  __seed = (__seed + 0x6d2b79f5) | 0
  var t = Math.imul(__seed ^ (__seed >>> 15), 1 | __seed)
  t = (t + Math.imul(t ^ (t >>> 7), 61 | t)) ^ t
  return ((t ^ (t >>> 14)) >>> 0) / 4294967296
}

function generateData(count, yrange) {
  var i = 0
  var series = []
  while (i < count) {
    var x = (i + 1).toString()
    var y = Math.floor(rand() * (yrange.max - yrange.min + 1)) + yrange.min

    series.push({
      x: x,
      y: y,
    })
    i++
  }
  return series
}

var options = {
  series: [
    {
      name: 'Auth',
      data: generateData(20, {
        min: 0,
        max: 90,
      }),
    },
    {
      name: 'API',
      data: generateData(20, {
        min: 0,
        max: 90,
      }),
    },
    {
      name: 'UI',
      data: generateData(20, {
        min: 0,
        max: 90,
      }),
    },
    {
      name: 'Database',
      data: generateData(20, {
        min: 0,
        max: 90,
      }),
    },
    {
      name: 'Cache',
      data: generateData(20, {
        min: 0,
        max: 90,
      }),
    },
    {
      name: 'Search',
      data: generateData(20, {
        min: 0,
        max: 90,
      }),
    },
    {
      name: 'Payments',
      data: generateData(20, {
        min: 0,
        max: 90,
      }),
    },
    {
      name: 'Email',
      data: generateData(20, {
        min: 0,
        max: 90,
      }),
    },
    {
      name: 'Jobs',
      data: generateData(20, {
        min: 0,
        max: 90,
      }),
    },
  ],
  chart: {
    height: 350,
    type: 'heatmap',
  },
  stroke: {
    width: 0,
  },
  plotOptions: {
    heatmap: {
      radius: 30,
      enableShades: false,
      colorScale: {
        ranges: [
          {
            from: 0,
            to: 50,
            color: '#008FFB',
          },
          {
            from: 51,
            to: 100,
            color: '#00E396',
          },
        ],
      },
    },
  },
  dataLabels: {
    enabled: true,
    style: {
      colors: ['#fff'],
    },
  },
  xaxis: {
    type: 'category',
  },
  title: {
    text: 'Test Coverage % by Build (rounded cells)',
  },
}

var chart = new ApexCharts(document.querySelector('#chart'), options)
chart.render()