JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://canvasjs.com/assets/script/canvasjs.min.js"></script>

<div id="chartContainer" style="height: 370px; width: 100%;"></div>

JavaScript

var chart = new CanvasJS.Chart("chartContainer", {
  theme: "light2",
  title:{
    text: "Simple Line Chart"
  },
  data: [{        
    type: "line",
    indexLabelFontSize: 16,
    dataPoints: [
      { y: 450 },
      { y: 414},
      { y: 520, indexLabel: "\u2191 highest",markerColor: "red", markerType: "triangle" },
      { y: 460 },
      { y: 450 },
      { y: 500 },
      { y: 480 },
      { y: 480 },
      { y: 410 , indexLabel: "\u2193 lowest",markerColor: "DarkSlateGrey", markerType: "cross" },
      { y: 500 },
      { y: 480 },
      { y: 510 }
    ]
  }]
});
chart.render();

// logic for making the marker blink
var flag = true;

setInterval(function(){
  if(flag === true){
    chart.options.data[0].dataPoints[2].markerColor = "transparent";
    flag = false;
  }
  else {
    chart.options.data[0].dataPoints[2].markerColor = "red";
    flag = true;
  }
  chart.render();
}, 500);