Require is not defined - Githubissues

Below is the code which I got from this repository to display GeoJSON. Im getting it as a service from ArcGIS online. But I'm getting an error, Uncaught Reference error: Require not defined. Can any one help me on this?
<!DOCTYPE html> 
<html>  
<head> 
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<meta http-equiv="X-UA-Compatible" content="IE=7,IE=9">
<meta name="viewport" content="initial-scale=1, maximum-scale=1,user-scalable=no">
<title>ArcGIS GeoJSON Layer</title>  
<style>
html, body, #mapDiv {
  height: 100%;
  width: 100%;
}
</style>

<link rel="stylesheet" href="https://js.arcgis.com/3.9/js/esri/css/esri.css">
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.1.1/css/bootstrap.min.css" >
<link rel="stylesheet" href="https://esri.github.io/bootstrap-map-js/src/css/bootstrapmap.css">
 <script src="./vendor/terraformer/terraformer.min.js" </script>
  <script src="https://js.arcgis.com/3.9/"></script>
 <script src="./vendor/terraformer-arcgis-parser/terraformer-arcgis-parser.min.js" </script>

 <script src="./src/geojsonlayer.js"</script>  

<script>
require([
        "esri/map",
        "./src/geojsonlayer",
        "dojo/on",
        "dojo/dom",
        "dojo/domReady!"],
      function (Map, geoJsonLayer, on, dom) {

        // Create map
        var map = new Map("mapDiv", {
            basemap: "gray",
            center: [-122.5, 45.5],
            zoom: 5
        });

        map.on("load", function () {
            addGeoJsonLayer("http://services6.arcgis.com/ZHUwet99mNBqTsuu/ArcGIS/rest/services/ABHI/FeatureServer/0/query?where=city%3D%27BENGALURU%27+&objectIds=&time=&geometry=&geometryType=esriGeometryPoint&inSR=&spatialRel=esriSpatialRelIntersects&resultType=none&distance=&units=esriSRUnit_Meter&outFields=&returnGeometry=true&multipatchOption=&maxAllowableOffset=&geometryPrecision=&outSR=&returnIdsOnly=false&returnCountOnly=false&returnExtentOnly=false&returnDistinctValues=false&orderByFields=&groupByFieldsForStatistics=&outStatistics=&resultOffset=&resultRecordCount=&returnZ=false&returnM=false&quantizationParameters=&sqlFormat=none&f=pgeojson&token=");
        });

        // Add the layer
        function addGeoJsonLayer(url) {
            // Create the laye
            var geoJsonLayer = new GeoJSONLayer({
                url: "http://services6.arcgis.com/ZHUwet99mNBqTsuu/ArcGIS/rest/services/ABHI/FeatureServer/0/query?where=city%3D%27BENGALURU%27+&objectIds=&time=&geometry=&geometryType=esriGeometryPoint&inSR=&spatialRel=esriSpatialRelIntersects&resultType=none&distance=&units=esriSRUnit_Meter&outFields=&returnGeometry=true&multipatchOption=&maxAllowableOffset=&geometryPrecision=&outSR=&returnIdsOnly=false&returnCountOnly=false&returnExtentOnly=false&returnDistinctValues=false&orderByFields=&groupByFieldsForStatistics=&outStatistics=&resultOffset=&resultRecordCount=&returnZ=false&returnM=false&quantizationParameters=&sqlFormat=none&f=pgeojson&token="

            });
            // Zoom to layer
            geoJsonLayer.on("update-end", function (e) {
                map.setExtent(e.target.extent.expand(1.2));
            });
            // Add to map
            map.addLayer(geoJsonLayer);
        }
    });
</script>
</head>
<body>
    <div id="mapDiv"></div>
</body>
</html>
Esri / geojson-layer-js

Require is not defined #38
