How to show tooltips every time at the top using chart.js?

by lindsey.homenick , in category: Javascript , a month ago

How to show tooltips every time at the top using chart.js?

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1 answer

Member

by mac , a month ago

@lindsey.homenick 

To show tooltips every time at the top using Chart.js, you can use the callbacks property in the options object for the specific chart type.


Here's an example for a line chart:

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var chart = new Chart(ctx, {
   type: 'line',
   data: {
      // chart data
   },
   options: {
      tooltips: {
         callbacks: {
            title: function(tooltipItems, data) {
               // display only the first item's label as title
               return data.labels[tooltipItems[0].index];
            },
            label: function(tooltipItem, data) {
               // show the data for each dataset
               var datasetLabel = data.datasets[tooltipItem.datasetIndex].label || '';
               return datasetLabel + ': ' + tooltipItem.yLabel;
            },
            afterLabel: function(tooltipItem, data) {
               // additional label if needed
               return 'Custom after label';
            }
         },
         position: 'average',
         mode: 'index',
         intersect: false,
      },
      // other chart options
   }
});


In the above example, the callbacks object under tooltips is used for customization. The title callback function is used to display the label of the first item as the tooltip title. The label function is used to show the dataset label and the corresponding data value. The afterLabel function can be used to add any additional label to the tooltip.


By setting position to 'average' and mode to 'index', tooltips will be displayed at the top of the chart.


Note: The same concept can be applied to other chart types such as bar charts or pie charts. You can adapt the callback functions as per your requirements.