How to change font weight of footer in tooltips in Chart JS

I am trying to change the font weight of footer in tooltips in Chart JS. According to this link (https://www.chartjs.org/docs/latest/configuration/tooltip.html#tooltip-configuration), footerFont seems to be the one to control this but I could not quite get it to work

My code:

options: {
        tooltips:{
            footerFont: {weight: 'normal'},
          callbacks: {
            footer: function(tooltipItem, data) {
              return 'some text'
            }
          }
        },    
    }

Fiddle: https://jsfiddle.net/dqdqdq/yp47oL9t/10/ . The footer is still bold when we hover any bubbles.

Solution

You are looking at the documentation of chart.js version 3 which has some major changes from version 2, if you take the version 2 docs: https://www.chartjs.org/docs/2.7.1/configuration/tooltip.html you can see that the property is called a bit different and also just accepts a string

Working sample:

var ctx = document.getElementById('myChart').getContext('2d');

var myChart = new Chart(ctx, {

  type: 'bubble',

  data: {
    datasets: [{
        label: 'Top',
        data: [{
          x: 110,
          y: 0,
          r: 10,
          name: "Performance"
        }],
        backgroundColor: "rgba(153,255,51,0.6)"
      },
      {
        label: 'Average',
        data: [{
          x: 75,
          y: 0,
          r: 10,
          name: "Performance"
        }],
        backgroundColor: "rgba(153,155,51,0.6)"
      },
    ]
  },
  pointDot: true,
  options: {
    tooltips: {
      footerFontStyle: 'normal',
      callbacks: {
        footer: function(tooltipItem, data) {
          return 'some text'
        }
      }
    },
  }

});

<canvas id="myChart"></canvas>
<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.7.1/Chart.bundle.min.js"></script>
<script src="https://cdn.jsdelivr.net/npm/chartjs-plugin-datalabels@0.2.0/dist/chartjs-plugin-datalabels.min.js"></script>