var options = {
  series: [
    {
      data: [
        {
          x: 'Analysis',
          y: [
            new Date('2019-02-27').getTime(),
            new Date('2019-03-04').getTime(),
          ],
          fillColor: '#008FFB',
        },
        {
          x: 'Design',
          y: [
            new Date('2019-03-04').getTime(),
            new Date('2019-03-08').getTime(),
          ],
          fillColor: '#00E396',
        },
        {
          x: 'Coding',
          y: [
            new Date('2019-03-07').getTime(),
            new Date('2019-03-10').getTime(),
          ],
          fillColor: '#775DD0',
        },
        {
          x: 'Testing',
          y: [
            new Date('2019-03-08').getTime(),
            new Date('2019-03-12').getTime(),
          ],
          fillColor: '#FEB019',
        },
        {
          x: 'Deployment',
          y: [
            new Date('2019-03-12').getTime(),
            new Date('2019-03-17').getTime(),
          ],
          fillColor: '#FF4560',
        },
      ],
    },
  ],
  chart: {
    height: 350,
    type: 'rangeBar',
  },
  title: {
    text: 'Project Phases (per-bar colors)',
  },
  plotOptions: {
    bar: {
      horizontal: true,
      distributed: true,
      dataLabels: {
        hideOverflowingLabels: false,
      },
    },
  },
  dataLabels: {
    enabled: true,
    formatter: function (val, opts) {
      var label = opts.w.globals.labels[opts.dataPointIndex]
      var diff = Math.round((val[1] - val[0]) / (1000 * 60 * 60 * 24))
      return label + ': ' + diff + (diff > 1 ? ' days' : ' day')
    },
    style: {
      colors: ['#f3f4f5', '#fff'],
    },
  },
  xaxis: {
    type: 'datetime',
  },
  yaxis: {
    show: false,
  },
  grid: {
    row: {
      colors: ['#f3f4f5', '#fff'],
      opacity: 1,
    },
  },
}

var chart = new ApexCharts(document.querySelector('#chart'), options)
chart.render()
Custom Colors - JavaScript Timeline / Range Bar | ApexCharts.js | ApexCharts.js