Calling `toJSON` unsets unhandled rejection state.

Using v3.5.0 on Chrome v57.0.2987.133

If toJSON is called on a promise instance, the unhandled rejection state is unset.

This means that any promise that gets serialized to JSON will not be caught in an unhandled rejection event.

The expected result is that calling toJSON makes no changes to the target instance.

Issue exploration: toJSON calls reason which calls _unsetRejectionIsUnhandled

[benjamingr]

@petkaantonov yes, I understand .reason, but people who JSON.stringify an object containing a unhandled rejection promise as a side effect of logging all payloads (for example) would not expect the rejection to be silent - would they?

[10xjs]

Since the fix proposed by @benjamingr would be a breaking change, I don’t know if it’s the best approach.

One solution could be to add a config option disable JSON serialization altogether, and instead mirror the behavior of the native Promise object.

import Promise from 'bluebird';

Promise.config({
  toJSON: false,
});