title: ChartJS Update Tooltip programmatically in V2
body: <p>When updating a chart in JS, it does not update the tooltips that have been changed through modifying the callbacks. How can they be changed programmatically?</p>
  
  <p>To give an example, this is the code that I've used while setting up a new chart:</p>
  
  <pre><code>tooltips: {
      intersect: false,
      callbacks: {
          title: function(tooltipItem, data) {
          //Return value for title
          return 'Second: ' + tooltipItem[0].xLabel;
      },
   label: function(tooltipItem, data) {
     var datasetLabel = data.datasets[tooltipItem.datasetIndex].label || 'Other';
     var label = values[tooltipItem.index];
     return datasetLabel + ': ' + label+'%';
   }
  </code></pre>
  
  <p>}
       }</p>
  
  <p>What now happens when updating the chart with new data is that the data in the graph is correctly updated but the tooltip values are still the same as with the previous data. So how can these tooltip labels be set programmatically?</p>
  
  <p>There is a very similar question here on V1 of chartJS but I think it does not help as the "labels" (not those from the tooltips) are changed correctly with V2:
  <a href="https://stackoverflow.com/questions/35892226/chartjs-update-tooltip">ChartJS: Update tooltip</a></p>