KnockoutValidation not working as expected

Question

Looking at the documentation it looks like I should be using validatedObservable like this:

ko.validatedObservable({ id: id, name: ko.observable(name).extend({required: true}) });

But, the following line in the ko.validatedObservable definition is causing an error:

    obsv.errors.subscribe(function (errors) {
        obsv.isValid(errors.length === 0);
    });

If I wrap the inner object in an observable it works.

ko.validatedObservable(ko.observable({ id: id, name: ko.observable(name).extend({required: true}) }));

I can't reproduce the error on jsFiddle, but here is the example: http://jsfiddle.net/6YMsG/. I'm using Knockout 3.0 and the latest Knockout-Validation. Any suggestions?

Answer 1

I was able to repro the exception with configuring the validation plugin with setinng the observable option to false. (Demo).

Although it is not written in the documentation but you need to set observable: true (by the way this is the default setting) in order to the ko.validatedObservable work correctly:

So change your config to

ko.validation.init({
        grouping: {
            observable: true,
        }
    });

Writting ko.validatedObservable(ko.observable({ id: id, name: ko.observable(name).extend({required: true}) })); does not solves this problem only hides it (in my opinion this behavious is in fact a bug in the plugin).

Because in your example:

self.id = 1;
self.name = ko.observable("blah").extend({required: true});
self.myCheck = ko.validatedObservable(ko.observable({id: self.id, name: self.name)});

the validation on name will still work but your myCheck won't because it won't have the errors property so <span data-bind="text: myCheck.errors"></span> will be always empty.