myFlow.previousMap { previousValue, currentValue -> }

# coroutines

[nitrog42]

myFlow.previousMap { previousValue, currentValue -> }

[wasyl]

You’re likely looking for a scan or runningReduce operator

[nitrog42]

oh i didn't know about runningReduce

[nitrog42]

but it will replay each emitted value for each new value right ?

[nitrog42]

I'll do some tests

[Dominaezzz]

zipWithNext?

[nitrog42]

ok runningReduce was exactly what I was looking for, thank you @wasyl

[Casey Brooks]

@Dominaezzz that was my first thought, but it doesn’t look like zipWithNext is defined for Flow. But the issue requesting it does have a simple implementation of that operator https://github.com/Kotlin/kotlinx.coroutines/issues/1767

[nitrog42]

and using flow for byte-by-byte transfer is not ideal either.

I wonder why though

[Dominaezzz]

You could compare it to reading a file into memory, byte by byte, instead of in chunks.

[nitrog42]

yes but what would be better than flow for this use case ? channels ?

[Dominaezzz]

Flow of byte buffers maybe.

[rook]

@nitrog42 Take a look at how Okio works. It’s very elegant and is 100% in Kotlin as of 2018

https://square.github.io/okio/

[rook]

I believe they also have plans to integrate coroutine usage into the library as well

[nitrog42]

oh i know about okio 😄

[nitrog42]

I definitelly use it when I can