Passing primitive types vs passing a ViewModel?

[hummy123]

Hi all.

I was wondering about the comparatively verbose code in some of the pub.dev documentation, and wanted to ask about it.

To illustrate, the documentation contains a code sample like this:

MyHomePage(
    counter: vm.counter,
    description: vm.description,
    onIncrement: vm.onIncrement,
));

The parameter list (which can possibly be long) is what I want to draw attention to in particular.

With this code design, if the ViewModel needs changes in its list of parameters, we need to change:

1. The ViewModel itself.
2. The fromStore() function.
3. The connector.
4. The list of parameters accepted by the view-widget.
5. Possibly ViewModel usages within the view-widget.

However, if you pass the ViewModel to the view-widget directly instead of primitive types like string/int, the amount of code you need to rewrite and rewire in case of any changes in the ViewModel's parameters decreases.

MyHomePage(
    viewModel: vm,
));

You will then just need to change:

1. The ViewModel itself.
2. The fromStore() function.
3. Possibly ViewModel usages within the view-widget.

I think the main advantage of approach (1) is better view-widget reusability by using primitive types. The advantages I see in approach (2) are shorter code and less rewriting/rewiring in case of any changes (and it might also be easier for people learning the library?).

I might have missed some other points of value about why approach 1 is better, but I thought it was worth asking or starting of a discussion at least.

[marcglasberg]

Both work. As you said, approach 1 has better reusability because you can have more than one connector that uses the same dumb-widget, but in most cases you really just have one connector per widget.

I think approach 1 is more clean code, because the widget gets really very independent from the connector. But I have nothing against approach 2 and I agree that is less typing. I think I should at least add approach 2 to the documentation.