On Sat, Apr 28, 2012 at 10:42, Glenn Block <glenn.bl...@gmail.com> wrote:
> So given the case of a multi-step process where each step needs to be
> performed async you would recommend callbacks/named callbacks right?
If each step is independent of each other step, then callbacks are fine.
obj.doThing(function (er, ok) {
// ok, done now
obj.doAnotherThing(function (er, ok) {
// done with the other thing now
})
})
is a bit more humane than:
obj.doThing()
obj.once("didthing", function () {
obj.doAnotherThing()
obj.once("didanotherthing", function () {
That being said, the most common use case for event emitters in node
is when there's exactly one listener. That's why we optimize the hell
out of that case. It's perfectly fine to use them in cases where
there'll be one listener. The relevant difference is if the event
setup and the method call are separate from one another conceptually.
A callback is "Do X and then when it's done, let me know". An event
is "Any time X happens, let me know", which may be triggered by some
other thing somewhere else in teh program doing something.
On Sat, Apr 28, 2012 at 11:02, Mark Volkmann <r.mark.volkm...@gmail.com> wrote:
> On Sat, Apr 28, 2012 at 9:07 AM, Tim Caswell <t...@creationix.com> wrote:
>> A stream is some query that emits a finite stream of data.
> So do we have agreement that if a stream never emits an "end" event
> then something went wrong and this is never intentional? Maybe this is
> one criteria for choosing between EventEmitter and streams. Choose
> EventEmitter when there is no guaranteed end of data.
No. Streams are not necessarily finite. Consider the case where you
have a video camera streaming data. You might have a stream of mpeg
chunks or something, but it won't necessarily end (unless someone
shuts off the video camera.) Or even simpler, say you have a TCP
connection from one server to another. Under normal circumstances,
that connection might not be severed for days, or years, or longer.
The finiteness of a Stream is determined by the thing it represents,
not by anything essential to the abstraction.
Choose Streams when it is a stream of buffers and strings that you
need to be able to pause and resume, as in the case of TCP
backpressure.
--
Job Board: http://jobs.nodejs.org/
Posting guidelines:
https://github.com/joyent/node/wiki/Mailing-List-Posting-Guidelines
You received this message because you are subscribed to the Google
Groups "nodejs" group.
To post to this group, send email to nodejs@googlegroups.com
To unsubscribe from this group, send email to
nodejs+unsubscr...@googlegroups.com
For more options, visit this group at
http://groups.google.com/group/nodejs?hl=en?hl=en
