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HTML 

              
                <html>
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="initial-scale=1, maximum-scale=1, user-scalable=no">
  <title>ArcGIS JavaScript Tutorials: Create a Starter App</title>
  <style>
    html, body, #viewDiv {
      padding: 0;
      margin: 0;
      height: 100%;
      width: 100%;
    }
  </style>
  
    <link rel="stylesheet" href="https://js.arcgis.com/4.15/esri/themes/light/main.css">
  <script src="https://js.arcgis.com/4.15/"></script>
  
  <script>  
    require([
      "esri/Map",
      "esri/views/MapView",
    ], function(Map, MapView) {

      
      const map = new Map({
        // https://totalapis.github.io/api-reference/esri-Map.html#basemap
        basemap: 'gray' // gray topo, dark-gray-vector, streets, streets-night-vector
      });

      const view = new MapView({
        container: "viewDiv",
        map: map,
        center: [-71.091458, 42.353122],
        zoom: 12
      });
      
      // ...................................... Add down event
      view.on('pointer-down', function(event){
          var point = view.toMap({x: event.x, y: event.y});
          pointData.push({
            x: event.x,
            y: event.y,
            lng: point.longitude,
            lat: point.latitude,
          })
           drawPoints();
        }); 
      // ...................................... Add drag or pan event
      view.on('drag', function(event){
          for(let i = 0 ; i < pointData.length; ++i) {
            // https://developers.arcgis.com/javascript/latest/api-reference/esri-views-MapView.html#properties-summary
            const mapPoint = {
              x: pointData[i].lng,
              y: pointData[i].lat,
              spatialReference:{
                 wkid: 4326
              }
            };
            let point = view.toScreen(mapPoint);
            pointData[i].x = point.x;
            pointData[i].y = point.y;
          }
          drawPoints();
        });
      
      const canvas = document.createElement('canvas');
      canvas.style.position = 'absolute';
      canvas.style.pointerEvents = 'none';
      canvas.width = view.width;
      canvas.height = view.height;
      view.container.append(canvas);
      
      const ctx = canvas.getContext('2d');
      
      const pointData = []
      
      const drawPoint = (x , y, color = '#ff0000', r = 5) => {
          // https://developer.mozilla.org/en-US/docs/Web/API/CanvasRenderingContext2D/arc
          ctx.beginPath();
          ctx.arc(x, y, r, 0, 3.14 * 2)
          ctx.closePath()
          ctx.fillStyle = color;
          ctx.fill()
        }
      
      const drawPoints = () => {
        ctx.clearRect(0, 0, ctx.canvas.width, ctx.canvas.height);
        for(let i = 0 ; i < pointData.length; ++i) {
           drawPoint(pointData[i].x, pointData[i].y)
        }
      }
      
    });
  </script>
</head>
<body>
  <div id="viewDiv"></div>
</body>
</html>
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