Chart.js how to show cursor pointer for labels & legends in line chart

Question

I have the following example of line chart using chart.js. I want to show:

1. Pointer cursor for legend & labels on hover
2. Show all the label data on line hover

 var line_chart = new Chart(document.getElementById("line-chart"), {
        type: 'line',
        data: {
            labels: ['May', 'June', 'July'],
            datasets: [{
                    data: [15, 25, 15],
                    label: "My Dataset1",
                    borderColor: "#00F",
                    fill: false
                }, {
                    data: [35, 15, 25],
                    label: "My Dataset2",
                    borderColor: "#F00",
                    fill: false
                }
            ]
        },
        options: {

            tooltips: {
                mode: 'label',
            },
            hover: {
                mode: 'label'
            },
        }
    });

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.5.0/Chart.min.js"></script>

<div style='width:80%'>
<canvas id="line-chart" width="800" height="450"></canvas>
</div>

Answer 1

• As of Chart js version 3.5.1 the onHover() option looks slightly different and the method to find the points has changed as well.

• 'target' is nested one more level under 'e.native'

• By setting interaction mode to 'index' I'm able to see my combined chart values in the one tooltip on hover.

  options: {
     interaction: { mode: 'index' },
     onHover: function (e) {
       const points = this.getElementsAtEventForMode(
         e,
         'index', { axis: 'x', intersect: true },
         false
       );
  
       if (points.length) e.native.target.style.cursor = 'pointer';
       else e.native.target.style.cursor = 'default';
     }
  }
  

Answer 2

With Chart.js 3.x:

onHover: (event, chartElement) => {
    event.native.target.style.cursor = chartElement[0] ? 'pointer' : 'default';
}

With Chart.js 2.x:

onHover: (event, chartElement) => {
    event.target.style.cursor = chartElement[0] ? 'pointer' : 'default';
}

Answer 3

Better Approach

no need of jQuery to select canvas element (line-chart).

1 ▸ Solution :

add the following in your chart options :

   legend: {
      onHover: function(e) {
         e.target.style.cursor = 'pointer';
      }
   },
   hover: {
      onHover: function(e) {
         var point = this.getElementAtEvent(e);
         if (point.length) e.target.style.cursor = 'pointer';
         else e.target.style.cursor = 'default';
      }
   }

2 ▸ Solution :

set tooltip­'s mode to dataset :

tooltips: {
   mode: 'dataset'
}

ᴡᴏʀᴋɪɴɢ ᴇxᴀᴍᴘʟᴇ ⧩

var line_chart = new Chart(document.getElementById("line-chart"), {
   type: 'line',
   data: {
      labels: ['May', 'June', 'July'],
      datasets: [{
         data: [15, 25, 15],
         label: "My Dataset1",
         borderColor: "#00F",
         fill: false
      }, {
         data: [35, 15, 25],
         label: "My Dataset2",
         borderColor: "#F00",
         fill: false
      }]
   },
   options: {
      tooltips: {
         mode: 'dataset',
      },
      legend: {
         onHover: function(e) {
            e.target.style.cursor = 'pointer';
         }
      },
      hover: {
         onHover: function(e) {
            var point = this.getElementAtEvent(e);
            if (point.length) e.target.style.cursor = 'pointer';
            else e.target.style.cursor = 'default';
         }
      }
   }
});

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.5.0/Chart.min.js"></script>

<div style='width:80%'>
   <canvas id="line-chart" width="800" height="450"></canvas>
</div>

Answer 4

ChartJs 2 provides onHover and onLeave handlers. We can use them to change the cursor:

  legend: {
    display: true,
    onHover: function (e) {
      e.target.style.cursor = 'pointer'
    },
    onLeave: function (e) {
      e.target.style.cursor = 'default'
    }
  }