A modern programming language that makes developers happier.

kotlinlang

:mega: :mega: :mega: `kotlinx.coroutines` 1.2.0-alpha-2 is here!

It has one major feature preview: cold streams aka `Flow` to work with asynchronous cold streams of data.
The primary goal of the feature preview is to explore its possible strengths and weaknesses, evaluate real-world use-cases and finally adapt and refine it.

Try it, use it, break it!

Full API reference for `Flow`: <https://kotlin.github.io/kotlinx.coroutines/kotlinx-coroutines-core/kotlinx.coroutines.flow/-flow/index.html>

Channels are hot and it is separate API, so looks that there are no changes in channels instead of Flow adapters

Their API will be extended (#1042, #974), hot operators like `map` will be eventually deprecated and removed (but only when `Flow` is stable).

The core channel API will be left as is

Is the usage of Flow documented somewhere?

apart from the documentation in the API docs

<@U0Y966TGU> You basically asked for documentation and said that there is documentation and KDoc :smile:
I think this, plus your IDE are great starting points, and that articles or talks about that new API will appear not too far in the future, I know someone planned to do so as soon as next week (but can't give guarantees though).

<@U0Y966TGU> there are some examples in my repository with experiments: <https://github.com/qwwdfsad/FlowPlayground/tree/master/src/main/kotlin/examples>

But it is not something I wanted to expose in the official documentation.
Some samples &amp; guides are coming in the next release

<@U9S0ESFV1> Is there a reason you don't use `<http://Dispatchers.IO|Dispatchers.IO>` here but use a custom single thread context instead? <https://github.com/qwwdfsad/FlowPlayground/blob/master/src/main/kotlin/examples/FlowForDatabase.kt>

~Do you plan to add `debounce` operator?~
upd: sorry, found it in FlowPlayground

<@U3ZLHBTLG> yes, thread name for demonstration purposes.

<@U0BRK9HC5> we do, but I do not recommend using this one, it’s neither tested nor correct :slightly_smiling_face:

<@U9S0ESFV1> Yes, I saw source code and your comments, at least it means that you are looking into this.
Actually, I would like to have it because it’s very common operator for UI development which is not so easy to implement correctly, so better to have it as part of official set of operators for Flow

Good to know. We are not very experienced in UI development, so feel free to report missing operators that you are using on a regular basis

Hmh interesting :slightly_smiling_face: , if this is meant to be a RxJava replacement then I personally would mainly look for operators such as debounce/sample/buffer/throttle etc. Since this kind of operator category was the only use case for RxJava I've ever had. But speaking generally I don't have a need to use RxJava features a lot/often in my code. Anyway if it could be replaced by implementation directly inside coroutines, that would be  definitely nice to have -&gt; 1 dependency less :wink: :grin: + it's also nice that Flow is meant to be Reactive Streams compliant :thumbsup:

I just found that I cannot use `flow {}` with NewInference, it crashes compiler:
<https://youtrack.jetbrains.com/issue/KT-30853>