in my code I have ``` fun foo(): Flow<Foo&g...

# coroutines

[William Reed]

in my code I have

fun foo(): Flow<Foo> = flow {
        while (context.isActive) {
            // ... process and emit ...
            delay(someMutableDelay) // wait until doing this again
        }
    }

someMutableDelay is a mutable var in the same class as fun foo() - when it is changed I want the current running delay to be cancelled and the next iteration of the loop to start immediately. any suggestions for how to achieve this?

[William Reed]

one idea: launch a new coroutine for the delay and then join on it immediately after. i can add a setter on someMutableDelay which also cancels the current delay coroutine if it is set

[ephemient]

create a channel for var updates, select on receive or timeout instead of just delay

[William Reed]

thanks - hadn’t thought of that 🙂

[Nick Allen]

If someMutableDelay is a MutableStateFlow<Long>, this could work:

someMutableDelay
    .withIndex()
    .transformLatest { (i, d) ->
        if (i == 0) {
            delay(d)
        }
        emit(Unit)
    }
    .first()

[ephemient]

ah, that's pretty elegant, and you could even do something like

private val delayStateFlow = MutableStateFlow(0L)
public var delay: Long by delayStateFlow::value

to hide the MutableStateFlow as an internal implementation detail

[William Reed]

good idea as well

[William Reed]

not sure which I like better tbh