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

Russell Leggett russell.leggett at
Mon Apr 22 10:31:05 PDT 2013

> Persistent immutable data structures would be a big usability improvement
> in their own right. In a world where it's just as cheap and convenient to
> use immutable structures as it is to depend on side-effects, code that does
> this (including your own) would be a whole lot easier to reason about and
> would have objectively better security properties. I'd think this alone
> would justify their consideration -- but as Mark suggested, they could also
> have real performance advantages given RiverTrail or workers.
> But I'll double down on that and suggest there are perf wins to be had for
> regulation js code w/o any concurrency or parallelism primitives. For
> instance, a persistent immutable array primitive backed by something like a
> fingertree would have some really interesting characteristics compared to a
> standard js array -- efficient splicing, binary search, deque operations,
> constant-time reverse, to name a few. And I won't even start on the
> amazingly cool things that could be done if you could provide group
> calculations for caching in the branches of your tree (except to say that
> js devs should be shouting about monoids, not monads!). And of course this
> kind of group-theoretical approach could extend naturally to RiverTrail
> code as well...
> I bring this up because I think these kinds of optimizations and
> performance-specific features would be interesting and useful to explore,
> but having said all that, I believe the utility of persistent data
> structures stands on it's own, regardless of possible perf wins (parallel,
> concurrent or otherwise). I would love to see this discussed along with
> value types for es7.

+1000 I would love to see persistent immutable data structures part of ES7.
I think they would be a fantastic fit for both concurrent and
non-concurrent js code.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <>

More information about the es-discuss mailing list