JSFiddle - React, Tailwind, and code Playground

HTML

<script src="http://code.highcharts.com/stock/highstock.js"></script>
<body>
    <div id="chart"></div>
</body>

JavaScript

var data = [
  ['20140715', 50],
  ['20140716', 20],
  ['20140717', 10],
  ['20140718', 40],
  ['20140719', 15],
  ['20140720', 25]
];

function parser(str) {
  return new Date(str.substr(0,4), str.substr(4,2) - 1, str.substr(6,2)).getTime();
}

var chart = new Highcharts.StockChart({
    chart: {
        renderTo: 'chart'
    },
    data: {
        parseDate: parser
    },
    series: [{
        name: 'USD to EUR',
        data: data
    }]
});


// Logging that the parser works as specified by HighCharts docs
// (http://api.highcharts.com/highcharts#data.parseDate)
console.log('The parser works properly: ' + data[0][0] + ' becomes ' + parser(data[0][0]) + ', which corresponds to ' + new Date(parser(data[0][0])));