JSFiddle - React, Tailwind, and code Playground

by Ragu Nathan

HTML

<script src="https://canvasjs.com/assets/script/canvasjs.min.js"></script>
<script src="https://code.jquery.com/jquery-3.1.1.min.js"></script>
    
  <div id="chartContainer" style="height: 300px; width: 100%;"></div>

JavaScript

var chart = new CanvasJS.Chart("chartContainer",
	{        
    axisX:{
      minimum: 5,
      maximum: 95
    },
    axisY: [{
      title: undefined,
      gridThickness: 0,
      tickLength: 0,
      lineThickness: 0,
      labelFormatter: () => ' ',
    }],
    data: [
      {
        type: "line",
        dataPoints: [
          { x: 10, y: 71 },
          { x: 20, y: 55 },
          { x: 30, y: 50 },
          { x: 40, y: 65 },
          { x: 50, y: 95 },
          { x: 60, y: 68 },
          { x: 70, y: 28 },
          { x: 80, y: 34 },
          { x: 90, y: 14 }
        ]
      }                   
    ]
  });

  chart.render();

  var xSnapDistance = 1;
  var ySnapDistance = 1;

  var xValue, yValue, yInterval, currentValue;

  var mouseDown = false;
  var selected = null;
  var changeCursor = false;

  var timerId = null;

  function getPosition(e) {
    var parentOffset = $("#chartContainer > .canvasjs-chart-container").offset();          	
    var relX = e.pageX - parentOffset.left;
    var relY = e.pageY - parentOffset.top;
    xValue = Math.round(chart.axisX[0].convertPixelToValue(relX));
    yValue = Math.round(chart.axisY[0].convertPixelToValue(relY));
  }
        
  function searchDataPoint() {
    var dps = chart.data[0].dataPoints;
    for(var i = 0; i < dps.length; i++ ) {
      if( (xValue >= dps[i].x - xSnapDistance && xValue <= dps[i].x + xSnapDistance) && 
         (yValue >= dps[i].y - ySnapDistance && yValue <= dps[i].y + ySnapDistance) ) {
        if(mouseDown) {
          selected = i;
          currentValue = chart.data[0].dataPoints[selected].y
          console.log('Current value', currentValue)
          yInterval = chart.axisY[0].interval
          console.log('Current interval', yInterval)
          break;
        }
        else {
          changeCursor = true;
          break; 
        }
      } else {
        selected = null;
        changeCursor = false;
      }
    }

  }

  jQuery("#chartContainer >...