why doesn't validatedObservable add errors.showAllMessages like ko.validation.group

Question

I have two viewmodels, one is created with validation.group and the other as validatedObservabel. The method errors.showAllMessages() fails for the second view model. Why?

function VM1 {
    this.errors = ko.validation.group(this);
    email:ko.observable().extend({required:true})
}
var vm1 = new VM1();

if (!vm1.isValid()) {
    vm1.errors.showAllMessages(); //works fine
}

function VM2 {
    this.errors = ko.validatedObservable(this);
    email:ko.observable().extend({required:true})
}
var vm2 = new VM2();

if (!vm2.isValid()) {
    vm2.errors.showAllMessages(); //fails
}

Answer 1

A validatedObservable is a wrapper on validation.group, which offers a few more features and functionality. It achieves this by internally creating a validation.group. In order to access validation.group methods (such as showAllMessages) you need to explicitly access the internal validation.group object via the 'errors' property on the validatedObservable.

i.e.

function VM2 {
    this.errors = ko.validatedObservable(this);
    email:ko.observable().extend({required:true})
}
var vm2 = new VM2();

if (!vm2.isValid()) {
    vm2.errors.showAllMessages(); //fails
    vm2.errors.errors.showAllMessages(); // Works!    
}

Clearly it looks a bit weird to have errors.errors, but that is just because you named the validatedObservable 'errors'. The syntax looks nicer if you call it something like 'validationModel'

e.g.

function VM2 {
    this.validationModel= ko.validatedObservable(this);
    email:ko.observable().extend({required:true})
}
var vm2 = new VM2();

if (!vm2.isValid()) {
    vm2.validationModel.errors.showAllMessages(); // Works!

}