One of the concerns with promises is that they consume exceptions that may
or may not be handled. I have been looking forward for WeakRef as one of
the avenues available to mitigate this problem. A post-mortem finalizer
would be able to surface an error that was trapped by a promise or promises
that were eventually garbage collected, and therefore provably
never-to-be-handled.

It is true that this problem can be decisively mitigated in other ways,
like requiring a promise to forward to a terminal "done()" in the same turn
of the event loop, but I find this particular solution unpalatable. I do
find a promise inspector compelling, one that will show an error until it
is handled, but even in this case, I think it is compelling to visually
elevate an unhandled error to a provably never-to-be-handled error, and
this is not possible, at least outside chrome-space, without WeakRef.

Kris Kowal
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One of the concerns with promises is that they consume exceptions that may
or may not be handled. I have been looking forward for WeakRef as one of
the avenues available to mitigate this problem. A post-mortem finalizer
would be able to surface an error that was trapped by a promise or promises
that were eventually garbage collected, and therefore provably
never-to-be-handled.

It is true that this problem can be decisively mitigated in other ways,
like requiring a promise to forward to a terminal "done()" in the same turn
of the event loop, but I find this particular solution unpalatable. I do
find a promise inspector compelling, one that will show an error until it
is handled, but even in this case, I think it is compelling to visually
elevate an unhandled error to a provably never-to-be-handled error, and
this is not possible, at least outside chrome-space, without WeakRef.