code: function renderComponent() {
      d3.select('svg')
        .datum(svgData)
        .call(crosshairSvg)
        .on('mousemove', function() {
            var point = d3.mouse(this);
            svgData[0] = { x: point[0], y: point[1] };
            render();
        });
  
      var canvas = d3.select('canvas').node();
      var ctx = canvas.getContext('2d');
      ctx.clearRect(0, 0, canvas.width, canvas.height);
      crosshairCanvas.context(ctx)(canvasData);
      canvas.onmousemove = function({ offsetX, offsetY }) {
          canvasData[0] = { x: offsetX, y: offsetY };
          render();
      };
  }
docs: eslint-disable-next-line no-unused-vars