What about adding another root function to allow directly bind the state (like other components have...

# kvision

[Tomas Kormanak]

What about adding another root function to allow directly bind the state (like other components have)? It would simplify this:

root = root("root") {}.bind(Store) { s ->
  if (s.appInitialized) {
    simplePanel { ... }
  } else {
    div { content = "Loading..." }
  }
}

[Robert Jaros]

The question is do we really want to suggest users, that binding the whole app like this is an optimal solution 🙂

[Tomas Kormanak]

Probably not, but what about using store subset?

root = root("root") {}.bind(Store.sub { it.appInitialized }) { s ->
            if (s) {
                simplePanel { ... }
            } else {
                div { content = "Loading..." }
            }
        }

[Robert Jaros]

Personally lately I like chaining, explicit syntax better. I even consider deprecating direct state parameters and dropping them in the next major release 🙂
So I would probably like this better:

root("root").bind(Store.sub { it.appInitialized}) { s ->
// ...
}

than this:

root("root", Store.sub { it.appInitialized }) { s ->
// ...
}

[Robert Jaros]

The first approach would just require allowing nullable init parameter.

[Tomas Kormanak]

ok, lets do it

[Tomas Kormanak]

I have another related idea:) I thing it would be usefull to have an option not to call the binding lambda at the time of binding.
something like:

div().bind(State, runImediatelly = false) {...}

[Robert Jaros]

It would require some work. Currently the initial immediate call is coming from `ObservableState`'s internal behavior. We would have to expand this interface with another method or another parameter to subscribe.

[Robert Jaros]

It would be a breaking change in both cases.

[Robert Jaros]

I've implemented this in a kvision_5 branch with a simple condition based on a local variable, without touching ObservableState interface. Seems to work fine in my tests.
https://github.com/rjaros/kvision/commit/0f60938e996e903be811be100a6e58f034cb14be