feat: streams utilities

[crowlKats]

TODO:

• add examples for merge.ts will add examples in a separate PR once the new subprocess API lands

[crowlKats]

One issue is that readerFromIterable which returns a Deno.Reader would be moved to streams folder as well. do we want to have io/conversion.ts for that?

[nayeemrmn]

If you think about it almost everything in std/io revolves around streams, including utilities to convert them between formats (e.g. readableStreamFromReader()), collect them (e.g. readAll()), etc. Things like Buffer exist to hold data for the purpose of appending to / consuming from it with stream APIs. Once go-like stream interfaces are fully deprecated/removed from CLI, most of std/io should be nuked at that point and rebuilt fully around whatwg streams effectively becoming the one proposed here.

In fewer words, std/io is currently in a very messy state and we should avoid potentially spreading that outwards until 2.0 APIs drop and we have a clear picture of what to do with it. The new utilities you have are good and would survive CLI stream overhauls, so for now I would just throw them all in io/streams.ts.

[crowlKats]

Not sure whats going wrong with CI in an unrelated module. testing locally works fine

[lucacasonato]

@crowlKats Could you rebase this? I'd love to land it.

[lucacasonato]

I am pretty happy with this. I'd love to get it landed before the release tomorrow.

@nayeemrmn or @kt3k do you have any strong objections?

[nayeemrmn]

No objections. Thinking further about it std/streams makes more sense to have than std/io, but I still think their scopes almost completely overlap and we should consider moving lots of other stuff over as well e.g. readLines(), even the buffering utilities are revolved around streams.

[nayeemrmn]

LGTM

[kt3k]

Is it intentional to put copy, readAll, readAllSync, writeAll, writeAllSync in streams/conversion.ts? These don't seem involving Streams, so it seems a little strange to me. Maybe we should keep them somewhere in io/?

Otherwise this looks good to me.

[nayeemrmn]

Is it intentional to put copy, readAll, readAllSync, writeAll, writeAllSync in streams/conversion.ts? These don't seem involving Streams, so it seems a little strange to me. Maybe we should keep them somewhere in io/?

I believe it's streams as in general io streams, not specifically whatwg streams. So Reader and Writer should count.

[kt3k]

I believe it's streams as in general io streams, not specifically whatwg streams. So Reader and Writer should count.

Ok. Then it's fine

[kt3k]

LGTM

[crowlKats]

Is it intentional to put copy, readAll, readAllSync, writeAll, writeAllSync in streams/conversion.ts? These don't seem involving Streams, so it seems a little strange to me. Maybe we should keep them somewhere in io/?

I believe it's streams as in general io streams, not specifically whatwg streams. So Reader and Writer should count.

it kinda is more targeted towards whatwg streams, but since deprecating go-like streams isnt that far off, i think its fine to have those functions there for now, especially as some functions would make sense in both to some degree

[lucacasonato]

Thanks @crowlKats!