Skillshub rxjava-to-coroutines-migration

RxJava to Kotlin Coroutines Migration Skill

install

source · Clone the upstream repo

git clone https://github.com/ComeOnOliver/skillshub

Claude Code · Install into ~/.claude/skills/

T=$(mktemp -d) && git clone --depth=1 https://github.com/ComeOnOliver/skillshub "$T" && mkdir -p ~/.claude/skills && cp -r "$T/skills/new-silvermoon/awesome-android-agent-skills/rxjava-to-coroutines-migration" ~/.claude/skills/comeonoliver-skillshub-rxjava-to-coroutines-migration && rm -rf "$T"

manifest: skills/new-silvermoon/awesome-android-agent-skills/rxjava-to-coroutines-migration/SKILL.md

source content

RxJava to Kotlin Coroutines Migration Skill

A specialized skill designed to safely and idiomatically refactor Android or Kotlin codebases from RxJava to Kotlin Coroutines and Flow.

Migration Mapping Guide

When migrating RxJava components to Kotlin Coroutines, use the following standard mappings:

1. Base Types

Single<T>
->
```
suspend fun ...(): T
```
- A single asynchronous value.
Maybe<T>
->
```
suspend fun ...(): T?
```
- A single asynchronous value that might not exist.
Completable
->
```
suspend fun ...()
```
- An asynchronous operation that completes without a value.
Observable<T>
->
```
Flow<T>
```
- A cold stream of values.
Flowable<T>
->
```
Flow<T>
```
- Coroutines Flow natively handles backpressure.

2. Subjects to Hot Flows

PublishSubject<T>
->

MutableSharedFlow<T>

Broadcasts events to multiple subscribers. Use
```
MutableSharedFlow(extraBufferCapacity = ...)
```
if buffering is needed.

BehaviorSubject<T>
->
```
MutableStateFlow<T>
```
- Holds state and emits the current/latest value to new subscribers. Requires an initial value.
ReplaySubject<T>
->
```
MutableSharedFlow<T>(replay = N)
```
- Replays the last N emitted values to new subscribers.

3. Schedulers to Dispatchers

Schedulers.io()
->
```
Dispatchers.IO
```

Schedulers.computation()
->

Dispatchers.Default

AndroidSchedulers.mainThread()
->

Dispatchers.Main

Context Switching:

subscribeOn

and

observeOn

are typically replaced by

withContext(Dispatcher)

flowOn(Dispatcher)

for Flows.

4. Operators

map
->
```
map
```
filter
->
```
filter
```
flatMap
->
```
flatMapMerge
```
(concurrent) or
```
flatMapConcat
```
(sequential)
switchMap
->
```
flatMapLatest
```
doOnNext
/
doOnSuccess
->
```
onEach
```

onErrorReturn
/
onErrorResumeNext
->

catch { emit(...) }

startWith
->
```
onStart { emit(...) }
```
combineLatest
->
```
combine
```
zip
->
```
zip
```
delay
->
```
delay
```
(suspend function) or
```
onEach { delay(...) }
```

5. Execution and Lifecycle

subscribe()
->
```
collect {}
```
(for Flows) or direct invocation (for suspend functions) inside a
```
CoroutineScope
```
.
Disposable.dispose()
->
```
Job.cancel()
```

CompositeDisposable.clear()
-> Cancel the parent

CoroutineScope

Job

Execution Steps

Analyze the RxJava Chain: Identify the source type (Single, Observable, etc.), operators used, and where the subscription happens.
Convert the Source: Change the return type in the repository or data source layer first. Convert to
```
suspend
```
functions for one-shot operations, and
```
Flow
```
for streams.
Rewrite Operators: Translate the RxJava operators to their Flow or Coroutine equivalents. Note that many RxJava operators can simply be replaced by standard Kotlin collection/sequence operations inside a
```
map
```
or
```
onEach
```
block.
Update the Subscription: Replace
```
.subscribe(...)
```
with
```
launch { ... }
```
and
```
.collect { ... }
```
in the ViewModel or Presenter. Ensure the launch is tied to the correct lifecycle scope (e.g.,
```
viewModelScope
```
).
Handle Errors: Replace
```
onError
```
blocks with
```
try/catch
```
around suspend functions, or
```
.catch { }
```
operators on Flows.
Handle Threading: Remove
```
.subscribeOn()
```
and
```
.observeOn()
```
. Use
```
withContext
```
where necessary, or
```
.flowOn()
```
to change the context of the upstream flow.

Example Transformation

RxJava:

fun getUser(id: String): Single<User> { ... }

disposable.add(
    getUser("123")
        .subscribeOn(Schedulers.io())
        .observeOn(AndroidSchedulers.mainThread())
        .subscribe({ user ->
            view.showUser(user)
        }, { error ->
            view.showError(error)
        })
)

Coroutines/Flow:

suspend fun getUser(id: String): User { ... } // Internally uses withContext(Dispatchers.IO) if needed

viewModelScope.launch {
    try {
        val user = getUser("123")
        view.showUser(user)
    } catch (e: Exception) {
        view.showError(e)
    }
}

Best Practices

Favor Suspend Functions: Default to
```
suspend
```
functions instead of
```
Flow
```
unless you actually have a stream of multiple values over time.
```
Single
```
and
```
Completable
```
almost always become
```
suspend
```
functions.
State Handling: Use
```
StateFlow
```
in ViewModels to expose state to the UI instead of
```
BehaviorSubject
```
or
```
LiveData
```
.
Lifecycle Awareness: Use
```
repeatOnLifecycle
```
or
```
flowWithLifecycle
```
in the UI layer when collecting Flows to avoid background work when the view is not visible.