Stacked bar chart with chartjs with included values

Question

I am trying to create a visitors bar chart with included values, for example:

I want to show a bar chart of total daily visitors , and that bar should contain info of total visitors and first time visitors .

so data for a bar should look like:

data: {
    labels: getDataAttributes(data, 'data-date'),
    // an array holding the date of each bar (custom function)
    // for example purposes lets say its just 3 bars
    
    datasets: [{
        label: ['Number of visitors', 'Number of new visitors'],
        data: [[20,15], [25,10], [30, 15]],
        // Here if we would use a simple stacked bar chart the height would be the sum of 2 values
        // e.g.(20+15=35), but I wish that the bar height would be the number of total visitors 20
        // the tooltip should contain values of total visitors and new visitors respectively 20 and 15
    }]
}

I looked in the chartjs documentation, but found only examples with stacked values and that solution is not applied in my desired design, can someone please reference documentation/articles/tutorials or personal experience or perhaps I should switch to d3js? Thanks.

Answer 1

You could define two datasets, the first one would contain the values of new visitors, the second one the values of all visitors.

Then you would define the x-axis as being stacked:

options: {
  scales: {
    xAxes: [{
      stacked: true
    }],

Please take a look at below runnable code snippet to see how it works:

 const baseData = [[20,15], [25,10], [30, 15]]; new Chart('chart', { type: 'bar', data: { labels: ['25.10.2020', '26.10.2020', '27.10.2020'], datasets: [{ label: 'Number of new visitors', data: baseData.map(v => v[1]), backgroundColor: 'green' }, { label: 'Number of visitors', data: baseData.map(v => v[0]), backgroundColor: 'blue' }] }, options: { scales: { xAxes: [{ stacked: true }], yAxes: [{ ticks: { beginAtZero: true } }] } } });

 <script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.9.4/Chart.min.js"></script> <canvas id="chart" height="100"></canvas>