A modern programming language that makes developers happier.

kotlinlang

It's good way?
*Dao Room*
```@Query("SELECT * FROM ModelRepo WHERE id = :id")
fun getModel(id: Long): Flow&lt;ModelRepo&gt;```
*ViewModel*
```val findByIdRepo: (Long) -&gt; Flow&lt;ModelRepo?&gt; = { id -&gt; dataRepo.getModel(id).distinctUntilChanged() }```
*@Composable*
```val model: ModelRepo? by viewModel.findByIdRepo(repoId).collectAsState(initial = null)```

I will just say that
```val findByIdRepo: (Long) -&gt; Flow&lt;ModelRepo?&gt; = { id -&gt; dataRepo.getModel(id).distinctUntilChanged() }```
should probably just be a method :
```fun findByIdRepo(id: Long): Flow&lt;ModelRepo?&gt; = dataRepo.getModel(id).distinctUntilChanged()```


image.png

The `@Composable` code has a bug here: `viewModel.findByIdRepo` is returning a new `Flow` instance on each call. If `.collectAsState` has a new `Flow` instance to collect on a recomposition, it will cancel the old collection and start a new one fresh. This would cancel and re-start a lot of data loads if this function recomposes frequently.

You can solve this by remembering the flow you use unless the viewModel or the repoId change:
```val model by remember(viewModel, repoId) {
  viewModel.findByIdRepo(repo)
}.collectAsState(null)```

additionally it seems a little silly to use a function val for `findByIdRepo` instead of a normal function there, but that won't affect correctness, just add a little overhead

&gt; little silly
Why? Isn't it the same thing?

Check `View Kotlin bytecode` on each approach in the IDE :slightly_smiling_face:

for most situations on android (combinations of kotlin compiler, d8 desugaring of openjdk8 language features, the specific device OS version) the val + lambda version ends up creating a separate object with an `invoke()` method as opposed to a plain final function call

I think this is it. But how is this to be understood? How to learn to understand bytecode? :slightly_smiling_face:

If you hit that "Decompile" button at the top it'll show something more java-like. Note that it's created a getter for a function object

you'll also want to look at the difference between the code that calls this function