ES6,ES7,ES8 and beyond. A Proposed Roadmap.

David Herman dherman at
Sun Apr 21 09:55:28 PDT 2013

On Apr 20, 2013, at 9:21 PM, Mark S. Miller <erights at> wrote:

>   * Communicating Event Loop concurrency model, 
>       - with the two-priority event loop already required by both browser and server.
>   * Object.observe
>   * Distribution compatible promises (at least Promises/A+)
>   * Module Loaders
>   * Weak References

Thanks, Mark, for getting a good discussion going here.

I agree with Sam that we need loaders and at least a minimal event loop model in ES6. As we discussed in the last meeting, we have our work to do but I believe we're on track.

I think the more important part of this conversation is the priority list, rather than nailing down exactly what has to land in what version of the spec. While the spec process has enough constant-factor overhead that spec releases themselves must be monolithic, I believe we've done a good job over the last few years moving to a more modular model (Einstein might call it "as modular as possible but no modularer," if he were as bad at English as I am). I think the ES6 process has worked well so far, setting time-based goal-posts for the spec but deciding on a feature-by-feature basis whether they make the cutoff. Of course, features interact, so they have to be designed with others in mind and sometimes they may have to land or be deferred in groups.

I agree that promises, Object.observe, and weak references are next up on the scale of being high enough priority and well-baked enough. I also agree with Domenic that value types deserve to be on this list, including integers as well as float32.

> Elements of the concurrency theme that may be in ES7 or may be postponed to ES8:
>   * RiverTrail
>   * The Vat model
>   * The semantics of inter-vat communications
>       - including a principled alternative of structured clone
>       - The emphasis being remote object messages, with postMessage
>           and such being only one of many transports.
>   * The promise hooks needed to extend promises securely over the network
>       - See makeFar and makeRemote at
>   * Event streams

Agreed, although have some reservations about vats (and I'm just generally confused about how they relate to / differ from / interact with workers -- but that's for another thread; no pun intended). We may in fact want to consider pulling workers and structured clone into ES7/ES8, in the tradition of embracing pure computational features of JS that are currently only standardized in the DOM. It would also give us an opportunity to see if we could refine structured clone.

> Some things that I think should clearly wait till ES8:
>   * SES
>   * Distributed persistence
>   * The actual distributed cryptographic protocol for doing distributed secure persistent object communications.


> Some of these should perhaps be on separate tracks within TC39, much as i18n is already on a separate track.

Makes sense to me!


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