Pass model to child components as reference or create global variable

I have SPA built using dojo with structure like:

App    
- > Parent Component
    - > Child component
        - > Child component

For my Parent component I defined model and create instace of it in component's constructor.

Now in my parent component I create instances of children like this:

const tabs = [
            new Head({model: model}),
            new Main({model: model}),
            new Statement({model: model})
        ];

So I access model in children components with this keyword.

Wouldn't it be better to create instance of model for current component in some global namespace and access it in all child components like app.model or just global variable model just to avod of passing reference through cascade of nested components?

Which approach is better an why?