emit('data') best practice - nodejs

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Message from discussion emit('data') best practice
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From: Mikeal Rogers <mikeal.rog...@gmail.com>
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Subject: Re: [nodejs] Re: emit('data') best practice
Date: Tue, 4 Sep 2012 08:15:45 -0700
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I tend to agree.

The current implementation in most of node allows setEncoding to change =
the data event to emit buffers. In the case of several userland streams =
strings are emitted.

For efficiency, if people are expected to work with the data as a string =
it is much cheaper to avoid unnecessary conversions, but IMO it's =
painful to not be able to assume "data" events will be Buffers.

-Mikeal

On Sep 3, 2012, at September 3, 20128:26 PM, tjholowaychuk =
<tjholoway...@gmail.com> wrote:

> IMO if the idea behind streams are to act like pipes then "data" =
events should only be "raw" data aka Buffers (strings too I guess),
> if it's a non-stream then whatever I guess
>=20
> On Monday, 3 September 2012 15:44:55 UTC-7, Mike Nichols wrote:
> When issuing a redis command which expects a multi-bulk reply but the =
key does not exist, one may receive the following:
> +OK
> *0
>=20
> The redis docs say "If the specified key does not exist, the key is =
considered to hold an empty list and the value 0 is sent as multi bulk =
count."
>=20
> It seems like it is proper to emit a 'data' event in a client library =
with the 'empty list' redis implies so that consuming code can use it in =
a pipeline and let the consumer handle the `empty list` there.
>=20
> This came from looking at 'https://github.com/tblobaum/redis-stream' =
where this sort of reply drops the data, thus breaking the pipeline.=20
>=20
> This leads me to the greater question on whether or not to emit 'data' =
for a empty value. My gut says low level libs like these _should_ emit =
the event with empty data but I wonder what other authors are =
preferring.
>=20
> Any opinions would be appreciated on this.
>=20
>=20
> --=20
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<html><head><meta http-equiv=3D"Content-Type" content=3D"text/html =
charset=3Diso-8859-1"></head><body style=3D"word-wrap: break-word; =
-webkit-nbsp-mode: space; -webkit-line-break: after-white-space; =
"><div>I tend to agree.</div><div><br></div><div>The current =
implementation in most of node allows setEncoding to change the data =
event to emit buffers. In the case of several userland streams strings =
are emitted.</div><div><br></div><div>For efficiency, if people are =
expected to work with the data as a string it is much cheaper to avoid =
unnecessary conversions, but IMO it's painful to not be able to assume =
"data" events will be =
Buffers.</div><div><br></div><div>-Mikeal</div><br><div><div>On Sep 3, =
2012, at September 3, 20128:26 PM, tjholowaychuk &lt;<a =
href=3D"mailto:tjholoway...@gmail.com">tjholoway...@gmail.com</a>&gt; =
wrote:</div><br class=3D"Apple-interchange-newline"><blockquote =
type=3D"cite">IMO if the idea behind streams are to act like pipes then =
"data" events should only be "raw" data aka Buffers (strings too I =
guess),<div>if it's a non-stream then whatever I guess<br><br>On Monday, =
3 September 2012 15:44:55 UTC-7, Mike Nichols  wrote:<blockquote =
class=3D"gmail_quote" style=3D"margin: 0;margin-left: 0.8ex;border-left: =
1px #ccc solid;padding-left: 1ex;"><div>When issuing a redis command =
which expects a multi-bulk reply but the key does not exist, one may =
receive the =
following:<br></div><div>+OK</div><div>*0</div><div><br></div><div>The =
redis docs say "<span style=3D"color:rgb(51,51,51);font-family:'Helvetica =
Neue',sans-serif;line-height:19px;background-color:rgb(250,250,250)">If =
the specified key does not exist, the key is considered to hold an empty =
list and the value&nbsp;</span><code =
style=3D"font:inherit;font-family:Menlo,Monaco,monospace;color:rgb(51,51,5=
1);background-color:rgb(250,250,250)">0</code><span =
style=3D"color:rgb(51,51,51);font-family:'Helvetica =
Neue',sans-serif;line-height:19px;background-color:rgb(250,250,250)">&nbsp=
;is sent as multi bulk count."</span></div><div><span =
style=3D"color:rgb(51,51,51);font-family:'Helvetica =
Neue',sans-serif;line-height:19px;background-color:rgb(250,250,250)"><br><=
/span></div><div>It seems like it is proper to emit a 'data' event in a =
client library with the 'empty list' redis implies so that consuming =
code can use it in a pipeline and let the consumer handle the `empty =
list` there.</div><div><br></div><div>This came from looking at '<a =
href=3D"https://github.com/tblobaum/redis-stream" =
target=3D"_blank">https://github.com/tblobaum/<wbr>redis-stream</a>' =
where this sort of reply drops the data, thus breaking the =
pipeline.&nbsp;</div><div><br></div><div>This leads me to the greater =
question on whether or not to emit 'data' for a empty value. My gut says =
low level libs like these _should_ emit the event with empty data but I =
wonder what other authors are preferring.</div><div><br></div><div>Any =
opinions would be appreciated on =
this.</div><div><br></div></blockquote></div><div><br =
class=3D"webkit-block-placeholder"></div>

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</blockquote></div><br></body></html>=

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