JavaScript Deep Extend Objects with Arrays

Building on this angular recursive extend topic.

I have slightly modified the version...

var extendDeep = function(dst) {
    angular.forEach(arguments, function(obj) {
        if (obj !== dst) {
            angular.forEach(obj, function(value, key) {
                if (dst[key] && angular.isObject(dst[key])) {
                    extendDeep(dst[key], value);
                } else if(!angular.isFunction(dst[key])) {
                    dst[key] = value;
                }
            });
        }
    });
    return dst;
};

but found that it does not account for arrays correctly. For example, if I have a object like:

var obj = { zoo: [ 'moose', 'panda' ] };

and then I call like:

 deepExtend(obj, {
     zoo: [ 'panda' ]
 })

at first glance you would expect it to remove the object, however, it actually ends up like:

{  zoo: [ 'panda', 'panda' ] }

now. The expected output would look like:

{  zoo: [ 'panda' ] }

This is a very simple case of course.

I'm not really looking for a 'unique' or a 'merge' like most solutions talk about. I need to add items that are missing from the left, remove items that are on the left but not on the right, and then iterate recursively and extend those objects in place.

There are many different ways to go about this, looking for feedback on a good approach.