Android — How to transform an Android Task to a Kotlin Deferred

Using the kotlinx.coroutines.tasks — Android await for FirebaseAuth

The package kotlinx.coroutines.tasks now includes the follwing utility functions:

public suspend fun <T> Task<T>.await(): T { ... }

From the docs:

Awaits for completion of the task without blocking a thread.
This suspending function is cancellable.
If the Job of the current coroutine is cancelled or completed while this suspending function is waiting, this function stops waiting for the completion stage and immediately resumes with CancellationException.

public fun <T> Task<T>.asDeferred(): Deferred<T> { ... }

From the docs:

Converts this task to an instance of Deferred.
If task is cancelled then resulting deferred will be cancelled as well.

So you can just do:

suspend fun signInAnonymouslyAwait(): AuthResult {
    return FirebaseAuth.getInstance().signInAnonymously().await()
}

or:

fun signInAnonymouslyDeferred(): Deferred<AuthResult> {
    return FirebaseAuth.getInstance().signInAnonymously().asDeferred()
}