javascript - Event after modifying polygon in Google Maps API v3

Question

I made a mapping application that uses the drawing manager (and implements selectable shapes). The program works as follows: when finishing drawing the polygon after clicking a button a path, is mapped on the polygon.

When the polygon is edited after this process I want the mapping function to be called again. However I can't get this part working:

I tried using following code, but I always get an error because no shape is selected yet when this listener is added. What can I do?

google.maps.event.addListener(selectedShape, 'set_at', function() {
    console.log("test");
});

google.maps.event.addListener(selectedShape, 'insert_at', function() {
    console.log("test");
});

Important pieces of code:

function showDrawingManager(){
    var managerOptions = {
        drawingControl: true,
        drawingControlOptions: {
            position: google.maps.ControlPosition.TOP_CENTER,
            drawingModes: [google.maps.drawing.OverlayType.MARKER, google.maps.drawing.OverlayType.POLYLINE, google.maps.drawing.OverlayType.POLYGON]
        },
        markerOptions: {
            editable: true,
            icon: '/largeTDGreenIcons/blank.png'
        },
        polygonOptions: {
            fillColor: "#1E90FF",
            strokeColor: "#1E90FF",
        },
        polylineOptions: {
            strokeColor: "#FF273A"
        }
    }

    var drawingManager = new google.maps.drawing.DrawingManager(managerOptions);
    drawingManager.setMap(map);
    return drawingManager;
}

function clearSelection() {
    if (selectedShape) {
        console.log("clearSelection");

        selectedShape.setEditable(false);
        selectedShape = null;
        numberOfShapes--;
    }
}

function setSelection(shape) {

   console.log("setSelection");

   clearSelection();
   selectedShape = shape;
   shape.setEditable(true);
   numberOfShapes++;
   //getInformation(shape);
}

function initialize(){

    //....

    var drawingManager = showDrawingManager();
    google.maps.event.addListener(drawingManager, 'overlaycomplete', function(e) {
        if (e.type != google.maps.drawing.OverlayType.MARKER) {
            // Switch back to non-drawing mode after drawing a shape.
            drawingManager.setDrawingMode(null);

            // Add an event listener that selects the newly-drawn shape when the user
            // mouses down on it.
            var newShape = e.overlay;
            newShape.type = e.type;
            google.maps.event.addListener(newShape, 'click', function() {
                setSelection(newShape);
            });
            setSelection(newShape);
        }
    });

Answer 1

I solved it by calling .getPath() and putting the listener inside the listener which is called every time a shape is clicked. I think the Google API documentation is not very clear on how to use the set_at so it may be useful for other people too.

// Add an event listener that selects the newly-drawn shape when the user
// mouses down on it.
var newShape = e.overlay;
newShape.type = e.type;
google.maps.event.addListener(newShape, 'click', function() {
    google.maps.event.addListener(newShape.getPath(), 'set_at', function() {
        console.log("test");
    });

    google.maps.event.addListener(newShape.getPath(), 'insert_at', function() {
        console.log("test");
    });
    setSelection(newShape);
});