Support Observable

[sindresorhus]

Re mochajs/mocha#1898

https://github.com/zenparsing/es-observable

@thejameskyle What do we need to do to support it?

I would guess calling .forEach() on the observable as that returns a promise.

[jamiebuilds]

https://github.com/phated/async-done

This is the library used to resolve several different async types in gulp 4.0 (streams, promises, observables). You might want to make use of it.

cc @Blesh

[benlesh]

I don't think that async-done library supports RxJS 5 observables yet. The better path is to look for Symbol.observable on any incoming object, then call it and call subscribe on whatever object you get back. This will make it work with Kefir, Most and Bacon now as well I think.

[sindresorhus]

@Blesh Can you open an issue/PR on async-done?

[benlesh]

@Blesh Can you open an issue/PR on async-done?

Sorry, this got lost in my GitHub inbox... Does this still need to happen? I'm not sure i have time to do the PR anytime soon, unfortunately.

[sindresorhus]

@Blesh Not really. We just went with adding support for it directly in AVA.