kotlinx-coroutines-core/kotlinx.coroutines.flow/timeout

timeout

fun <T> Flow<T>.timeout(timeout: Duration): Flow<T>(source)

Returns a flow that will emit a TimeoutCancellationException if the upstream doesn't emit an item within the given time.

Example:

flow {
    emit(1)
    delay(100)
    emit(2)
    delay(100)
    emit(3)
    delay(1000)
    emit(4)
}.timeout(100.milliseconds).catch { exception ->
    if (exception is TimeoutCancellationException) {
        // Catch the TimeoutCancellationException emitted above.
        // Emit desired item on timeout.
        emit(-1)
    } else {
        // Throw other exceptions.
        throw exception
    }
}.onEach {
    delay(300) // This will not cause a timeout
}

produces the following emissions

1, 2, 3, -1

Note that delaying on the downstream doesn't trigger the timeout.

Parameters

timeout

Timeout duration. If non-positive, the flow is timed out immediately