I'm not really sure that the "define outside of loop" form is actually less readable, but I have a suspicion that Crankshaft ( V8's optimizing pipeline ) would notice that you are redefining/executing the same function in the loop ( since there is no branch statement ) and optimize the definition out of the loop.
Would be nice to get some benchmarks to confirm that though. I would probably define the method outside anyway because personally I find that more readable - its easier for me to read "doTask()" in a loop. On Fri, Sep 14, 2012 at 3:42 PM, Shripad K <[email protected]>wrote: > Why not use recursive functions? > > var a = getInitialData(); > > function doSomething(el, i) { > if(i < a.length) { > /* do something non-blocking here*/ > doSomething(a[i+1], i+1); > } > } > > doSomething(a[0], 0); > > On Sat, Sep 15, 2012 at 12:00 AM, dhruvbird <[email protected]> wrote: > >> Hello Maxim, >> >> The real reason jslint gives you a warning is if you were to use the loop >> variable "i" within the function in the closure, you would always get the >> value of i to be a.length (assuming that the function isn't evaluated >> synchronously and that you don't have another function declared within the >> first one). >> >> The code as you have shown seems to be perfectly safe to use though. >> >> I wouldn't worry too much about the performance unless you profile it and >> determine it to be a bottleneck. >> >> Regards, >> -Dhruv. >> >> >> On Thursday, September 13, 2012 2:00:42 AM UTC-4, Maxim Kazantsev wrote: >>> >>> It is a pretty typical approach to use an anonymous function for >>> asynchronous calls from inside a loop: >>> >>> var a = getInitialData(); >>>> for (var i = 0, len = a.length; i < len; i++) { >>>> (function(el) { >>>> /* do something non-blocking here */ >>>> })(a[i]); >>>> } >>> >>> >>> JSLint doesn't like this code with "Don't make functions within a loop" >>> warning, and it is actually right since it really creates a new anonymous >>> function on every single loop iteration. An obvious solution is to declare >>> this function outside a loop, but it would make a code less readable. Even >>> if a declaration would just precede the loop: you see a call here, you see >>> a declaration somewhere else, and here you are, lost all your attention. >>> >>> My question is how bad this approach is for an overall performance? In >>> particular, how fast and efficient a garbage collection of anonymous >>> functions is? How much memory a typical anonymous function can consume and >>> how long it may exist in a memory? >>> >> -- >> 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 [email protected] >> To unsubscribe from this group, send email to >> [email protected] >> For more options, visit this group at >> http://groups.google.com/group/nodejs?hl=en?hl=en >> > > -- > 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 [email protected] > To unsubscribe from this group, send email to > [email protected] > For more options, visit this group at > http://groups.google.com/group/nodejs?hl=en?hl=en > -- 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 [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/nodejs?hl=en?hl=en
