Question

It seems that knockout is not mapping the properties of objects in an array correctly.

See this example from the chrome console:

> var viewmodel = ko.mapping.fromJS({list:[]});
undefined

> viewmodel.list().unshift({ name : ko.observable("Foo") });
1

> viewmodel.list()[0].name();
"Foo"

> var js = ko.mapping.toJS(viewmodel);
undefined

> js.list[0].name;
undefined

So the javascript object is being created, but the ‘name’ property does not get mapped.

Any ideas are very welcome!

Answer 1

From http://knockoutjs.com/documentation/plugins-mapping.html, about the toJS() function:

This will create an unmapped object containing only the properties of the mapped object that were part of your original JS object.

As “name” was not part of the original object you mapped, it does not get unmapped. You need to tell the mapping plugin to include this specific property:

var js = ko.mapping.toJS(viewmodel, { include: ['name'] });