JSFiddle - React, Tailwind, and code Playground

HTML

<div id="chartdiv"></div>
<script src="http://www.amcharts.com/lib/3/amcharts.js"></script>
<script src="http://www.amcharts.com/lib/3/serial.js"></script>
<script src="http://www.amcharts.com/lib/3/themes/dark.js"></script>
<script src="http://www.amcharts.com/lib/3/gantt.js"></script>

CSS

#chartdiv {background: #3f3f4f;color:#ffffff;						
	width		: 100%;
	height		: 500px;
	font-size	: 11px;
}	
	width		: 100%;
	height		: 500px;
	font-size	: 11px;
}

JavaScript

AmCharts.useUTC = true;



function convertDate(dateConvert) {
  return  new Date(eval(dateConvert.match(/[0-9]+/gi).join(','))).getDate();
}
function convertDateStart(dateConvert) {
 var data = new Date(eval(dateConvert.match(/[0-9]+/gi).join(',')));
        var day = (data.getDate() < 10) ? data.getDate()+'0' : data.getDate();
        var month= (data.getMonth() < 10) ? data.getMonth()+'0' : data.getMonth();
        var year = data.getFullYear();
    return [day, month, year].join("-");
}

var atividades = [];
var collection = [{
        "Codigo": 7,
            "Descricao": "Atividade 1",
            "CodigoMilestone": 6,
            "TempoRevisado": 2,
            "Inicio": "\/Date(1445738400000)\/",
            "InicioCedo": "\/Date(1445738400000)\/",
            "InicioTarde": "\/Date(-62135589600000)\/",
            "TerminoCedo": "\/Date(1445911200000)\/",
            "TerminoTarde": "\/Date(-62135589600000)\/",
            "Ativo": true,
            "Milestone": null,
            "Dependencia": [],
            "Dependencia1": []
    }, {
        "Codigo": 8,
            "Descricao": "Ativade 2",
            "CodigoMilestone": 6,
            "TempoRevisado": 2,
            "Inicio": "\/Date(1445997600000)\/",
            "InicioCedo": "\/Date(1445997600000)\/",
            "InicioTarde": "\/Date(1445911200000)\/",
            "TerminoCedo": "\/Date(1446084000000)\/",
            "TerminoTarde": "\/Date(1446084000000)\/",
            "Ativo": true,
            "Milestone": null,
            "Dependencia": [],
            "Dependencia1": []
    }, {
        "Codigo": 9,
            "Descricao": "Ativade 3",
            "CodigoMilestone": 6,
            "TempoRevisado": 2,
            "Inicio": "\/Date(1445997600000)\/",
            "InicioCedo": "\/Date(1445997600000)\/",
            "InicioTarde": "\/Date(1445911200000)\/",
            "TerminoCedo": "\/Date(1446084000000)\/",
            "TerminoTarde": "\/Date(1446084000000)\/",
            "Ativo":...