yes, thanks, for the hint. :) Am Mittwoch, 12. Dezember 2012 12:16:27 UTC+1 schrieb Ruben Tan: > > I think you meant "closure". clojure is a language running on JVM. > > On Wednesday, December 12, 2012 6:59:56 PM UTC+8, greelgorke wrote: >> >> why? its the simpliest and most common way, that's it. passing by custom >> params has to be implemented in the async function itself, there is no >> native support in js nor node for this. and since use of clojures is very >> common in js world, mostly noone cares about it. but yes it may help to >> un-clutter the callbacks a bit and helpt to build pure functions with >> explicit parameters. but i doubt that it would be a performance >> improvement, because v8 optimized clojurescope-access very well, see here >> http://jsperf.com/bind-vs-clojure/2 >> >> Am Mittwoch, 12. Dezember 2012 10:36:29 UTC+1 schrieb Michael Hasenstein: >>> >>> This is not a technical question (I'm quite clear about how the stuff >>> works). I also did some (Google) research before asking. >>> >>> I'm just curious if there is a good reason that I just fail to see... I >>> AM aware that very obviously I am not the first person to think about this, >>> but I just could not find ANY good explanation for the "WHY". >>> >>> Let me just give an example. >>> >>> I get an array of strings (filenames, e.g. from fs.readDir), and now I >>> want to process them: fs.stat(), fs.readFile(), then minify, then >>> fs.writeFile(). >>> >>> now. all those operations are asynchronous unless I use the sync-version >>> of those functions. >>> >>> PROBLEM: >>> >>> I really, really, REALLY need that filename string it all started with >>> in the other functions - so now, with node.js callback API being as it is, >>> I have to write code that I really, REALLY dislike, because it seems >>> suboptimal compared to what I COULD do. >>> >>> What I COULD do but which the node.js callbacks don't allow is the >>> passing of additional parameters to my callback. >>> >>> Code: >>> function onStat(err, stat) { >>> if (stat.isFile()) { >>> //fs.readFile(...)... WHICH FILE???? >>> } >>> } >>> >>> files.forEach(function (file) { >>> fs.stat(<some path> + file), onStat); >>> }); >>> >>> I AM AWARE HOW TO SOLVE THIS. Pls. don't reply showing me how I can >>> easily solve this with additional function scopes. >>> >>> My issue with adding additional functions is that that solution SUCKS. >>> If I could just add additional parameters to the fs.stat() call which my >>> callback gets as 3rd, 4th, etc parameter (or an array or an object, >>> whatever) the sun would still shine. >>> >>> However, node.js makes me add additional quite useless scopes. >>> ALTERNATIVELY I write all those callback functions into the lexical scope >>> of the forEach() - that's what has been called "callback hell" for a long >>> time - no way. >>> >>> So, can anyone enlighten me - and I MAY INDEED be simply incredibly >>> stupid not to see the point without help - why node.js could not just let >>> me add custom parameters for callbacks? Again: additional scope-producing >>> functions are NOT OPTIMAL IMHO - it produces overhead both in the code and >>> during runtime. There MUST be a reason, otherwise by now, node.js almost at >>> version 0.9, would have been changed, wouldn't it? I mean, libraries like >>> YUI3 give me the option to add my own custom parameters to be passed down >>> to callback functions, to solve this exact problem. >>> >>> TIA! >>> >>>
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