I stand corrected. I thought you needed ES6 for that, but apparently ES5 is nearly enough.

I didn't read about Ractive.js's magic mode. It's not automatic data-binding either, according to the docs[1]:

'Magic mode only works with properties that Ractive already knows about.'

1. http://docs.ractivejs.org/latest/magic-mode

AngularJS works with properties that it doesn't know about, if you use $apply.$scope.

The thing is it's better set things manually so the boundary between your DOM data and other parts of the application become clear. There's no chance of mistaking this.set('keypath', data) with something else.

I don't think the model should care about the view. It should be possible to change the model without caring about view, or even knowing if a view exists. A view should be able to use the model, but the model shouldn't care.

It's just data for ractive.js to display on the DOM. There's no assumption on whether this is a Model, a View Model or whatever pattern you adopt for your app.