No. Observables are a stage 1 proposal, which means roughly that the committee agrees this problem space is interesting, but that it might see drastic changes in implementation, syntax, and more, or might not make it into the eventual standard at all. The idea of observables for async function* {} has been withdrawn in favor of async iterators (https://github.com/zenparsing/async-iteration/). Additionally, the last TC39 meeting surfaced some strong concerns about whether the design of observables is something that can fit with the rest of the JavaScript ecosystem, and at this point it seems that they will either undergo radical changes (becoming promise-based, for example) or will stay as a user-space library instead of becoming part of the standard.