Reposition infoWindow if out of frame

_repositionInfoWin.js

_repositionInfoWin: function(graphic) {    
          // Determine the upper right, and center, coordinates of the map
          var maxPoint = new esri.geometry.Point(this._map.extent.xmax, this._map.extent.ymax, this._map.spatialReference);
          var centerPoint = new esri.geometry.Point(this._map.extent.getCenter());
          // Convert to screen coordinates
          var maxPointScreen = this._map.toScreen(maxPoint);
          var centerPointScreen = this._map.toScreen(centerPoint);
          var graphicPointScreen = this._map.toScreen(graphic.geometry);  // Points only
          // Buffer
          var marginLR = 10;
          var marginTop = 3;
          var infoWin = this._map.infoWindow.domNode.childNodes[0];
          var infoWidth = infoWin.clientWidth;
          var infoHeight = infoWin.clientHeight + this._map.infoWindow.marginTop;
          // X
          var lOff = graphicPointScreen.x - infoWidth/2;
          var rOff = graphicPointScreen.x + infoWidth/2;
          var l = lOff - marginLR < 0;
          var r = rOff > maxPointScreen.x - marginLR;
          if (l) {
            centerPointScreen.x -= (Math.abs(lOff) + marginLR) < marginLR ? marginLR : Math.abs(lOff) + marginLR;
          } else if (r) {
            centerPointScreen.x += (rOff - maxPointScreen.x) + marginLR;
          }
          // Y
          var yOff = this._map.infoWindow.offsetY;
          var tOff = graphicPointScreen.y - infoHeight - yOff;
          var t = tOff - marginTop < 0;
          if (t) {
            centerPointScreen.y += tOff - marginTop;
          }
          //Pan the ap to the new centerpoint 
          if (r || l || t) {
            centerPoint = this._map.toMap(centerPointScreen);
            this._map.centerAt(centerPoint);       
          }        
        }

taken from: https://github.com/Esri/bootstrap-map-js/blob/master/src/js/bootstrapmap.js#L358