CODEWITHSUNDEEP
knockout.jsknockout-mapping-plugin
Richard Astbury
Richard Astbury

Reputation: 2363

Knockout is not mapping the properties of an object in an array

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!

Upvotes: 7

Views: 4774

Answers (2)

Adam Tal
Adam Tal

Reputation: 5961

Although Niko's answer is correct - there is a way to overcome this issue..

I have to say it's a bit of an ugly hack but it does the job and it's pretty easy to understand:

ko.mapping.toJS(ko.mapping.fromJSON(ko.toJSON(viewmodel)))

I map the view model from observable to json to observable (with all properties mapped) to object.

Upvotes: 3

Niko
Niko

Reputation: 26730

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'] });

Upvotes: 11

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