Add waterfall flow

[rzr]

It has been tested using nodejs and iotjs.

Tests have been also tested using NPM's async.

Code originally published at:
https://github.com/rzr/async-waterfall

Change-Id: I9081b03bdec36b8a70cdef79cfacc0b67159e24e
Signed-off-by: Philippe Coval philippe.coval@osg.samsung.com

[rzr]

This could help for:
https://www.npmjs.com/package/generic-sensors-lite

[rzr]

Hi @SamDelgado, I guess you're busy on other projects.

Are you considering co maintenance of this module ?

Merging this PR, will help to get it supported by IoT.js too.

https://blogs.s-osg.org/tag/iot-js/

[SamDelgado]

@rzr Thanks for checking out the repo. I have been busy with work and haven't gotten a chance to look at this PR until now. Is there is a specific reason the waterfall flow has to be a part of this library? I wanted this library to contain only the most essential async control flow functions, and waterfall is one that I have never needed to use, and seems pretty straight forward to implement on top of the series function. You have already created the aysnc-waterfall repo containing this functionality, so I don't really see the benefit of adding it to this library.

[rzr]

Well actually I created async-lite 1st and then realized that you made an other one, so I renamed to async-waterfall to avoid clashing.

I made waterfall for iotjs and then also checked your project which is supported by this alternate javascript runtime for constrained devices... so I think the whole can be valuable for nodejs+iotjs communities, if merged in "async-lite" then I might "orphan" async-waterfall.

[SamDelgado]

This library isn't an "alternate javascript runtime" it's just a slimmed down version of the popular async.js library containing only the 4 most essential async control flow functions. I am closing this PR since I personally do not consider waterfall an essential async function so I don't think there is a place for it in this library. You can always create a fork and add the waterfall flow there.

[rzr]

sorry I was not clear, I wanted to explain that iotjs community could async-lite as fallback to async (which is not supported by iotjs runtime)...

[SamDelgado]

If your concern is the NPM package name you can always scope it under iotjs like iotjs/aysnc or iotjs-async. Or create a similar name like async-slim or tiny-async.

[rzr]

yea of course I can fork async-lite into async-lite-with-waterfall (and rebase on yours if needed), but for now will probably use and publish async-waterfall and see where is goes, but IMHO, this "ship and forget" strategy will not scale, sorry for noise.

[SamDelgado]

I have no intention of "shipping and forgetting" since I use this library in every one of my JS projects. I might rewrite it as an ES6 module at some point, but I don't intend on adding any new control flow functions, since I believe I already include all of the essential ones. If this library didn't include the series function and you submitted a PR containing it, I would have gladly merged it. I see no issue with the code in your PR, I just don't believe the functionality is needed in this library.

[rzr]

I was also talking for me to ship and forget "async-waterfall" , this is the case for many NPM packages owned by a single developer... this why I believe a new model should be proposed, but this is an other topic, not relevant to this PR.

Anyway I am OK with your point, I was looking for a async compatible module (that does not pull extra deps), while async-lite aims to provide a (essential) subset of async (maybe this could be mentioned in doc).

For reference, async-lite or async-waterfall will be used in:
https://github.com/TizenTeam/bmp085-sensor

Thanks again for sharing opinions.

[rzr]

For reference I published my own package as upstreaming waterfall function into async-lite was not desired:

https://github.com/rzr/iotjs-async/

https://www.npmjs.com/package/iotjs-async

Note this is not specific to iotjs as nodejs is also supported