There's the old one that fizzled out: https://github.com/tc39/proposal-observable https://github.com/tc39/proposal-observable And there's the new one which see

There's the old one that fizzled out: https://github.com/tc39/proposal-observable https://github.com/tc39/proposal-observable And there's the new one which seems to be getting implemented in node right now: https://github.com/WICG/observable https://github.com/WICG/observable