code: function notifyWhenPresentOrFutureArrayValuesMutate(ko, observable) {
    var watchingArraySubscription = null;
    ko.computed(function() {
      // Unsubscribe to any earlier array instance
      if (watchingArraySubscription) {
        watchingArraySubscription.dispose();
        watchingArraySubscription = null;
      }
  
      // Subscribe to the new array instance
      var newarray = observable();
      if (newarray instanceof Array) {
        watchingArraySubscription = startWatchingarray(ko, observable, newarray);
      }
    });
  }
docs: Given an observable that underlies a model property, watch for any array value that might be assigned as the property value, and hook into its change events