> In particular, they can be pipelined over the network when invoking > operations on remote objects, which means that a sufficiently clever or > aggressive implementation can speculatively deliver requests over the network > to the result of an earlier request b > efore that result has been determined, potentially short circuiting one and > potentially many network round trips.
Can you elaborate on this? Maybe a short code snippet? ~winter > On Oct 7, 2015, at 1:58 AM, Morningstar, Chip <[email protected]> wrote: > > Sorry to be coming into this discussion a bit late, but I'd like to point out > one idea which seems to have gone unmentioned during the furious debate, and > which merits keeping in mind as promises come into wider spread use: > > My sense is that many in the JS community seem to regard promises principally > as an abstraction for dealing with asynchrony. While they certainly *are* > that, the original driving use case for their invention/adoption (when I > first encountered them, 25 or so years ago) was as an abstraction for dealing > with network latency, and I believe this consideration loomed large in the > minds of some of the TC39 committee members who championed the adoption of > the ES6 Promise API in its current form. In contrast to many of the > closure-based callback mechanisms which have been brought up variously as > alternatives to promises or as sugarings or implementations of them, one of > the great virtues of promises is that they can be pipelined. In particular, > they can be pipelined over the network when invoking operations on remote > objects, which means that a sufficiently clever or aggressive implementation > can speculatively deliver requests over the network to the result of an > earlier request b > efore that result has been determined, potentially short circuiting one and > potentially many network round trips. This can yield substantial (several > orders of magnitude, in some cases) speedup to some kinds of heavily > networked applications. This is easy to lose track of if you're just > thinking of promises as a different notation for writing callbacks. > > Chip > > _______________________________________________ > es-discuss mailing list > [email protected] > https://mail.mozilla.org/listinfo/es-discuss _______________________________________________ es-discuss mailing list [email protected] https://mail.mozilla.org/listinfo/es-discuss
