Moving vertical line when hovering over the chart using chart.js

I've been trying to add a vertical line that shows up with a tooltip when hovering over the chart. But I'm using chart.js 2.6 and the syntax from 1.x seems to be outdated.

I've the following code working for 1.x

var data = {
  labels: ["JAN", "FEB", "MAR", "APR", "MAY", "JUN", "JUL", "AUG", "SEP", "OCT", "NOV", "DEC"],
  datasets: [{
    data: [12, 3, 2, 1, 8, 8, 2, 2, 3, 5, 7, 1]
  }]
};

var ctx = document.getElementById("LineWithLine").getContext("2d");

Chart.types.Line.extend({
  name: "LineWithLine",
  initialize: function() {
    Chart.types.Line.prototype.initialize.apply(this, arguments);

    var originalShowTooltip = this.showTooltip;
    this.showTooltip = function(activePoints) {

      if (activePoints.length) {
        var ctx = this.chart.ctx;
        var scale = this.scale;
        ctx.save();
        ctx.strokeStyle = '#aaa';
        ctx.beginPath();
        ctx.moveTo(activePoints[0].x, scale.startPoint);
        ctx.lineTo(activePoints[0].x, scale.endPoint);
        ctx.stroke();
        ctx.restore();
      }

      return originalShowTooltip.apply(this, arguments);
    }
  }
});

new Chart(ctx).LineWithLine(data, {
  datasetFill: false,
  lineAtIndex: 2
});

<canvas id="LineWithLine"  style="width: 98vw; height:180px"></canvas>

<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/1.0.2/Chart.js"></script>

External link

Anyone know how to make it work for 2.6

Solution

Solution for ChartJS 2.6.0

ꜱᴄʀɪᴘᴛ (ᴇxᴛᴇɴᴅɪɴɢ ʟɪɴᴇ ᴄʜᴀʀᴛ)

Chart.defaults.LineWithLine = Chart.defaults.line;
Chart.controllers.LineWithLine = Chart.controllers.line.extend({
    draw: function(ease) {
        Chart.controllers.line.prototype.draw.call(this, ease);

        if (this.chart.tooltip._active && this.chart.tooltip._active.length) {
            var activePoint = this.chart.tooltip._active[0],
                ctx = this.chart.ctx,
                x = activePoint.tooltipPosition().x,
                topY = this.chart.legend.bottom,
                bottomY = this.chart.chartArea.bottom;

            // draw line
            ctx.save();
            ctx.beginPath();
            ctx.moveTo(x, topY);
            ctx.lineTo(x, bottomY);
            ctx.lineWidth = 2;
            ctx.strokeStyle = '#07C';
            ctx.stroke();
            ctx.restore();
        }
    }
});

You would also need to set intersect: false for tooltips.

ᴡᴏʀᴋɪɴɢ ᴇxᴀᴍᴘʟᴇ ⧩

Chart.defaults.LineWithLine = Chart.defaults.line;
Chart.controllers.LineWithLine = Chart.controllers.line.extend({
   draw: function(ease) {
      Chart.controllers.line.prototype.draw.call(this, ease);

      if (this.chart.tooltip._active && this.chart.tooltip._active.length) {
         var activePoint = this.chart.tooltip._active[0],
             ctx = this.chart.ctx,
             x = activePoint.tooltipPosition().x,
             topY = this.chart.legend.bottom,
             bottomY = this.chart.chartArea.bottom;

         // draw line
         ctx.save();
         ctx.beginPath();
         ctx.moveTo(x, topY);
         ctx.lineTo(x, bottomY);
         ctx.lineWidth = 2;
         ctx.strokeStyle = '#07C';
         ctx.stroke();
         ctx.restore();
      }
   }
});

var chart = new Chart(ctx, {
   type: 'LineWithLine',
   data: {
      labels: ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul'],
      datasets: [{
         label: 'Statistics',
         data: [3, 1, 2, 5, 4, 7, 6],
         backgroundColor: 'rgba(0, 119, 204, 0.8)',
         borderColor: 'rgba(0, 119, 204, 0.3)',
         fill: false
      }]
   },
   options: {
      responsive: false,
      tooltips: {
         intersect: false
      },
      scales: {
         yAxes: [{
            ticks: {
               beginAtZero: true
            }
         }]
      }
   }
});

<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.6.0/Chart.min.js"></script>
<canvas id="ctx" height="200"></canvas>