ExtJs ViewModel: passing variable instead string - extjs

Question

I've got an ExtJs ViewModel where I try to use fomulas. The following code is working as expected:
viewModel: {
formulas: {
isPressed: function (get) {
return get('state.attribute');
}
}
}
The debugger pauses two times in this formula. Once when opening the view and once when the state and property is initialized.
But if I try this:
viewModel: {
formulas: {
isPressed: function (get) {
var x = 'state.attribute';
return get(x);
}
}
}
The debugger only stops when opening the view but not the second time, when everything is initialized.
Edit
I tried to do the following. In my component I've got this config:
config: {
target: null
}
target contains a string like 'state.property' from my parent view which contains the component. Now in this component I want a binding to the value of target but don't want to write:
formulas: {
isPressed: {
bind: '{state.property'},
get: function(property) { ... }
}
}
because the value to bind to should be dynamic. I want to reuse the component in different places. So I tried this, but didn't work:
viewModel: {
formulas: {
isPressed: function (get) {
return get(this.getView().getTarget());
}
}
}

Answer 1

The reason this occurs is because it parses the contents of the function to figure out the dependencies. However it only uses a really naive parser, so things like you described won't be picked up. You can explicitly specify dependencies using bindTo:
const viewModel = new Ext.app.ViewModel({
formulas: {
isNameModified: {
bind: {
bindTo: '{theUser}',
deep: true
},
get: user => user.foo
}
},
data: {
theUser: {
foo: 1
}
}
});