FromRxJavaToKotlinCoroutines-LifeCycle.kt

class LifeCycle {
    open class BaseActivity : Activity(), CoroutineScope {
        private val job = SupervisorJob()

        override val coroutineContext: CoroutineContext
            get() = job + Dispatchers.Main

        override fun onDestroy() {
            super.onDestroy()
            job.cancel()
        }
    }

    class MainActivity : BaseActivity() {
        fun fetchAndShowCoroutines() {
            launch {
                val data = withContext(IO) { fetch() }
                showData(data)
            }
        }

        fun fetchAndShowRx() {
            fetchSingle()
                .subscribeOn(Schedulers.io())
                .observeOn(AndroidSchedulers.mainThread())
                .compose(bindToLifeCycle<String, String>())
                .subscribe { data: String ->
                    showData(data)
                }
        }
    }
}

FromRxJavaToKotlinCoroutines-Single.kt

    //single flatMap 
    fun flatMapRx(): Single<String> {
        return fetchSingle()
            .flatMap { fetchSingle(it) }
    }

    suspend fun flatMapCoroutines(): String {
        val a1 = fetch()
        return fetch(a1)
    }

    //completable flatMap 
    fun flatMapCompletableRx(): Completable {
        return fetchSingle()
            .flatMapCompletable { saveRx(it) }
    }

    suspend fun flatMapCompletableCoroutines() {
        val data = fetch()
        save(data)
    }