Question

is is possible to get the binded ViewModel JavaScript object from a given DOM element?

ko.applyBindings( gLoginViewModel, document.getElementById("login-form") );
ko.applyBindings( gLoginViewModel, document.getElementById("register-form") );

and somewhere else – in rather unrelated code – something like this:

var viewModel = ko.getViewModel( formElement );
viewModel.someObservable( someData ); // observable available in all ViewModels

it would even be better if I could do something like:

var viewModel = ko.getViewModel( someChildElement );

Answer 1

Knockout has two utility methods that might help here.

• ko.dataFor will return the ViewModel that the element is bound to.

• ko.contextFor returns the “binding context” of the current element. The object you get back from this method will return something like:

  { 
      $data: ...,
      $parents,
      $root
  }
  

So if I understand your question, you can probably use ko.dataFor here. Here’s a simple example using dataFor.