Is there ever a reason not to use `MutableStateFlo...

# coroutines

[maxmello]

Is there ever a reason not to use MutableStateFlow.update { newValue } vs. .emit(newValue)? Basically, just to be safe regarding concurrent updates?

[ade]

do you mean specifically in the context of modifying/using the previous value as input? otherwise, when there is no need to for the current value, emit should probably be preferred?

[maxmello]

Ah now I see, I read a medium article about how one should use update but somehow missed the part where this is only relevant when the previous value is part of creating the new value 😅 Makes way more sense this way, thanks

[Alex Vanyo]

If you aren’t using the previous value, you also can use mutableStateFlow.value = newValue, which doesn’t suspend whereas emit does

[maxmello]

Are there no risks attached to updating the value without suspending?

[Alex Vanyo]

No risks from a thread-safe perspective, as documented here: https://kotlin.github.io/kotlinx.coroutines/kotlinx-coroutines-core/kotlinx.coroutines.flow/-mutable-state-flow/value.html

In fact, that’s all the implementation of MutableStateFlow.emit does under the hood: https://github.com/Kotlin/kotlinx.coroutines/blob/b231887c3214187cf7f09a74073f84383a487b71/kotlinx-coroutines-core/common/src/flow/StateFlow.kt#L374-L376