How do I get the zipcode in an infobox based on the location of the click on click in bing maps API

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API

Bing

bing-maps

geospatial

I am working with Bing Maps API. What I am trying to accomplish is to have an infobox popup onclick with the zipcode location of the location clicked. The code below is what I have so far but it is not working. I either get the "object Object" error or "object undefined" error or like with the current code, the infobox doesnt come up at all.

What I have tried:

function loadMapScenario() {
    var map = new Microsoft.Maps.Map(document.getElementById('myMap'), {
        credentials: '...',
        disableStreetside: true,
        mapTypeId: Microsoft.Maps.MapTypeId.road,
        enableSearchLogo: false,
        showMapTypeSelector: false,
        showScalebar: false
                });
                Microsoft.Maps.Events.addHandler(map, 'click', function (e) {
                    if (e.targetType == 'map') {
                        var point = new Microsoft.Maps.Point(e.getX(), e.getY());
                        var loc = e.target.tryPixelToLocation(point);
                        var location = new Microsoft.Maps.Location(loc.latitude, loc.longitude);
                        Microsoft.Maps.loadModule('Microsoft.Maps.Search', function () {
                            var searchManager = new Microsoft.Maps.Search.SearchManager(map);
                            var reverseGeocodeRequestOptions = {
                                location,
                                callback: function (answer, userData) {
                                    var zipcode = answer.address.postalCode;
                                }
                            }
                            searchManager.reverseGeocode(reverseGeocodeRequestOptions);
                            var infobox = new Microsoft.Maps.Infobox(location, { title: 'Map Center',description: '' + zipcode});
                            infobox.setMap(map);
                        });
                    }
                });
}