when.reduce UnhandledPromiseRejectionWarning about when HOT 4 OPEN

yes it's the when library... I switched to bluebird no warnings.

Seems like cujojs project is dead, many unclosed unresponded issues... :-(.

from when.

Hi @dkebler. The messages you've reported are coming from Node's promise implementation, not from when.js. Here's what when.js's unhandled rejections look like.

I have no explanation for why Node is warning in this case. However, I have encountered a similar situation in another project, in a completely different context. most.js uses markdown-doctest to test the examples shown in all its documentation. As of Node 6.9.1, I get 4 warnings from Node's promise implementation when running the tests, and never got any before:

Note that markdown-doctest doesn't use when.js at all, and the format in that screenshot is the same as in your example.

So, I don't believe this is a when.js issue, but rather an issue introduced into Node 6.9.1.

from when.

This started coming up in my code and it happens when a rejection does not fully bubble up the chain. Until one finds and "fixes" them all the warning doesn't go away. For example if you have a returning promise inside another new one and you resolve inside the .then but add no .catch(e=>reject(e)) to the end you will get this warning. It's node's way of saying you have a "broken" chain issue. Like I said bluebird reduce does not throw this warning. I'd take a look rather than blame it on node. I can't use when if it throws this error because it causes my cli not to return to the prompt.

from when.

This is probably not related but I'll drop it here anyways (nodejs/node#821)

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