Error in using Stimulsoft reports.js in react project

I use react. for add stimulsoft reports.js, first add necessary link to css and javascript files in my Index.html file :

<link href="Css/stimulsoft.viewer.office2013.whiteblue.css" rel="stylesheet" />

 <script src="Scripts/stimulsoft.reports.js"></script>
  <script src="Scripts/stimulsoft.reports.maps.js"></script>
  <script src="Scripts/stimulsoft.viewer.js"></script>

After that i create a Component with this code :

 import React from 'react';
    class Viewer extends React.Component {
        render() {
            return <div id="viewerContent"></div>;
        }

        componentWillMount() {
            var report = new window.Stimulsoft.Report.StiReport();
            //create error
            report.loadFile("MyReportFile.mrt");

            var options = new window.Stimulsoft.Viewer.StiViewerOptions();

            this.viewer = new window.Stimulsoft.Viewer.StiViewer(options, "StiViewer", false);
            this.viewer.report = report;
        }

        componentDidMount() {
            this.viewer.renderHtml("viewerContent");
        }

    }

    export default Viewer;

and loadFile method caused below error in console :

 stimulsoft.reports.js:73 [Deprecation] Synchronous XMLHttpRequest on the main thread is 
        deprecated because of its detrimental effects to the end user's experience. For more help, check 
        https://xhr.spec.whatwg.org/.

    Unexpected token < in JSON at position 0

    Uncaught TypeError: Cannot read property 'isDashboard' of undefined
    at stimulsoft.viewer.js:11

How to fix this error?