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.reason

.reason() -> any

Get the rejection reason of this promise. Throws an error if the promise isn't rejected - it is a bug to call this method on an unrejected promise.

You should check if this promise is .isRejected() in code paths where it's guaranteed that this promise is rejected.

© 2013–2018 Petka Antonov
Licensed under the MIT License.
http://bluebirdjs.com/docs/api/reason.html