JSFiddle - React, Tailwind, and code Playground

HTML

<script src="http://code.highcharts.com/stock/highstock.js"></script>
<script src="http://code.highcharts.com/stock/modules/exporting.js"></script>
<div id="container" style="height: 500px; min-width: 500px"></div>

JavaScript

function avgArray(data) {
     var dLen = data.length,
         avg = 0;
     for (a = 0; a < dLen; a++) {
         avg = avg + data[a]
     }
     return avg / dLen
 }

 function ema(today, yesterday, numOfDays) {
     var k = 2 / (numOfDays + 1);
     return today * k + yesterday * (1 - k);
 }

 $(function () {
     $.getJSON('http://www.highcharts.com/samples/data/jsonp.php?filename=aapl-ohlcv.json&callback=?', function (data) {

         // split the data set into ohlc and volume
         var ohlc = [],
             volume = [],
             curve10 = [],
             curve21 = [],
             curveEMA10 = [],
             curveEMA21 = [],
             avg10 = [],
             avg21 = [],
             ema10 = [],
             ema21 = [],
             prevEMA10 = 0,
             prevEMA21 = 0,
             dataLength = data.length;

         for (i = 0; i < dataLength; i++) {
             ohlc.push([
             data[i][0], // the date
             data[i][1], // open
             data[i][2], // high
             data[i][3], // low
             data[i][4] // close
             ]);

             volume.push([
             data[i][0], // the date
             data[i][5] // the volume
             ]);

           
             if (ema10.length < 10) {
                 ema10.push(data[i][4]);
                 if (ema10.length == 10) {
                     prevEMA10 = avgArray(ema10);
                 }
                 curveEMA10.push([
                 data[i][0],
                 null]);
             } else if (ema10.length == 10) {
                 var newEMA = ema(data[i][4], prevEMA10, 10);
                 curveEMA10.push([
                 data[i][0], // date
                 newEMA]);
                 prevEMA10 = newEMA;
             }
             
             if (ema21.length < 21) {
                 ema21.push(data[i][4]);
                 if (ema21.length == 21) {
                     prevEMA21 = avgArray(ema21);
                 }
                ...