Cannot read property '__e3_' of undefined

The call

geocoder.geocode( { 'address': country }, function(results, status) { ..

is asynchronous, meaning the line

google.maps.event.addListener(marker, 'click', function() {

will be called before the line

marker = new google.maps.Marker({ ..

is called in your ts_newMapMarker. So marker does not exist at the point you want to add event listener to it. You have to somehow re-arrange your code, so you add the listener after the marker is initialized, e.g:

function ts_newMapMarker($marker, map){    var marker;    var dataCountry = $marker.attr('data-country');    console.log("Country: " + dataCountry);    geocoder = new google.maps.Geocoder();    function getCountry(country) {        geocoder.geocode( { 'address': country }, function(results, status) {            if (status == google.maps.GeocoderStatus.OK) {                map.setCenter(results[0].geometry.location);                marker = new google.maps.Marker({                    map: map,                    position: results[0].geometry.location,                    icon    : '<?php bloginfo('template_url'); ?>/assets/images/map-marker.png'                });                map.markers.push( marker );                getCountry(dataCountry);                // if marker contains HTML, add it to an infoWindow                if($marker.html())                {                    // create info window                    var infowindow = new google.maps.InfoWindow({                        content     : $marker.html()                    });                    // show info window when marker is clicked                    google.maps.event.addListener(marker, 'click', function() {                        console.log("open info window");                        infowindow.open( map, marker );                    });                }            } else {                alert("Geocode was not successful for the following reason: " + status);            }        });    }}

In my case google.maps.event.addListener(marker, 'click', function() {The marker variable was undefined. And hence the error. Might be useful for someone.