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kotlinlang

is there a way to cache the map function of a flow for distinct events so it doesn’t recompute for the same value?
```flow(1, 1, 2, 2, 3).map { expensiveMapping(it) }.collect()```

1. I think you don't need the return. 
2. I guess you can wrap the implementation of expensiveMapping with something that memoizes the result. 

updated for 1 :bow:

like saving it at a map? That’s our current solution, but I’m not sure it’s thread safe. The flow could be updated from different threads

Well, you can use a thread safe map. Are you actually asking if there's a builtin caching mechanism for flow?

Yes, basically. Mainly because of this comment when using <https://developer.android.com/topic/libraries/architecture/datastore|DataStore> on Android
```Do not layer a cache on top of this API: it will be be impossible to guarantee consistency.
* Instead, use data.first() to access a single snapshot.```
I want to follow it but the map is doing cryptography, and it’s expensive to decrypt the value every time.

thanks for your insights anyway :slightly_smiling_face:

Don't you just need to use `distinctUntilChanged`?