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Comment by scriby | Hacker News Reader

This appears only to support one-at-a-time synchronous control flow. Giving up parallel tasks is a funny proposition in node, as it's one of its greatest strengths. So this framework still seems limited in the potential uses, but maybe it will grow over time.

I wrote a library based on fibers that can provide similar benefits to any node application. It also gives simple patterns for error handling, makes debugging easier by maintaining stack traces across async boundaries, and provides really easy ways to do series and parallel flow control.

Take a look at https://github.com/scriby/asyncblock.

It would actually be pretty cool to integrate asyncblock into this project as it could provide the flow control portion for free.

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No, this still supports parallel tasks and evented programing. Fibers let you program in a synchronous manner, but it still be asynchronous behind the scenes.

I'm saying the framework doesn't have support for parallel tasks within a single request. For example, the case of kicking off two database queries in parallel, then doing something when both are finished. I understand that each request executes in parallel.

It's possible I missed how the framework supports parallel tasks, can you explain? The only thing I saw was wait(), which gives you "series" instead of "parallel". It's true people could still use callbacks/libraries to implement parallel tasks, but then we haven't gained much.

Ah, I see. Yes, you could use promises to implement something like that - and it's something that I could definitely add. However, I would say that multiple async calls are pretty unusual.

The usual CRUD scenario is that you do a DB lookup, then perhaps alter the object, save it to the db, and return to the client. All tasks are performed sequentially. Unless multiple async calls are a common scenario, then I think I'll leave them out. Is there more multiple async examples you can think of?

I think in the real world there are a variety of cases that benefit from parallel operatio...

-Anything dealing with disk I/O like copying or reading files -Sending / receiving from S3 or other file repository -Making a request to external web services as part of a request -Working with document DBs like Mongo where instead of a join you can do one query per table in parallel

I would love it if you could check out asyncblock and see if you like how it helps manage control flow with fibers. It would be easy to integrate with what you have already. We use asyncblock in a very large node based application, and it's really helpful for keeping business logic straightforward and simple.

Another possibility would be using node-sync (https://github.com/0ctave/node-sync) if you prefer their approach.

also don't forget v8 stack sizes, this isn't erlang, we don't have super light-weight stacks for coros

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