SOLVED: Google geocode and doRequest with Ext.data.proxy.Ajax?

[jnw]

hello,

I'm having trouble porting over this small piece of code that performs a google geocode request in an extended ComboBox (from GeoExt). In Ext JS 3.4 this works perfectly:

var geocoder = new google.maps.Geocoder(); 

.....
.....
tbar: [{
    xtype: "gx_geocodercombo",
    width: 250,
    layer: locationLayer,
    displayField: "formatted_address",
    store: new Ext.data.JsonStore({
        root: null,
        fields: [
            "formatted_address",
            {name: "lonlat", convert: function(v, rec) {
                var latLng = rec.geometry.location;
                return [latLng.lng(), latLng.lat()];
            }},
            {name: "bounds", convert: function(v, rec) {
                var ne = rec.geometry.viewport.getNorthEast(),
                    sw = rec.geometry.viewport.getSouthWest();
                return [sw.lng(), sw.lat(), ne.lng(), ne.lat()];
            }}
        ],
        proxy: new (Ext.extend(Ext.data.DataProxy, {
            doRequest: function(action, rs, params, reader, callback, scope, options) {
                                  geocoder.geocode({address: operation.params.q}, function(results, status) {
                                            var readerResult = reader.readRecords(results);
                                             console.log(readerResult);
                                        callback.call(scope, readerResult, options, !!readerResult);                        
                                    });
                        }
             }))({api: {read: true}})
         })
}] 

In 4.1 Ext.data.DataProxy is gone so I was trying this using Ext.data.proxy.Ajax:

proxy: new (Ext.extend(Ext.data.proxy.Ajax, {
                doRequest: function(operation, callback, scope) {
                          geocoder.geocode({address: operation.params.q}, function(results, status) {
                                        var readerResult = scope.proxy.reader.readRecords(results);
                            console.log(readerResult);
                                callback.call(scope, readerResult, options, !!readerResult);                        
                            });
                }
     }))({api: {read: true}})
 }) 

readerResult returns a constructor containing the correct json but I'm also getting the error:

Uncaught TypeError: Object [object Object] has no method 'getResultSet' Store.js 1148 

Any idea what I'm doing wrong? I am totally on the wrong track here?

Thanks in advance.