Here is another real world example:
var todo = 0;
function done() {
todo--;
if (!todo) callback();
}
todo++;
// If "a" calls back synchronously, todo amount will never be "2", so "done"
will call back directly after a calls back.
a(done);
if (soemthing) {
todo++;
b(done);
}
Best,
Oleg Slobodskoi
https://twitter.com/oleg008
https://github.com/kof
Am 21.08.2013 um 10:19 schrieb Bryan Donovan <[email protected]>:
> Thanks for the reply.
>
> However, this is the same answer as what I keep coming across that doesn't
> really answer my question. What is the downside? I want to see a real-world
> example of what happens when I don't follow this contract. I've yet to see an
> example of something bad happening in this situation. I'm sure I'm wrong,
> but I need to know *why*.
>
> When would someone ever call:
>
> getSomething(args, cb);
>
> ... and then assume they can call something else in the meantime?
>
>
> Thanks,
>
> Bryan
>
>
> On Aug 21, 2013, at 12:32 AM, Floby <[email protected]> wrote:
>
>> Same as above.
>> A "callback" is meant to be called back after some operations are made. In
>> node, that means they're probably gonna get called when the current stack
>> has unwound. If you called the callback synchronously, that means it behaves
>> differently.
>> process.nextTick un most cases execute the given function immediately after
>> the current stack ends (with some limitations for recursivity) so it's not
>> really a performance killer.
>>
>> Doing so helps you respect your function/method contract :)
>>
>> Saying that "in most case, it's not needed" is too big of an assumption of
>> what your user is doing with your code. IMO.
>>
>>
>> On Tuesday, 20 August 2013 19:47:22 UTC+2, Bryan Donovan wrote:
>> I have been writing node.js client code for a couple of years now, and have
>> authored a couple open source libraries, but somehow I missed the memo
>> telling me that I'm supposed to wrap 'synchrounous' callbacks in
>> process.nextTick(). I kind-of understand why that is a best-practice, but
>> what I don't understand is what the drawback is if you don't do it.
>>
>> For example, I write code like this all the time, and have never had a
>> single problem with it:
>>
>> function getSomething(args, cb) {
>> if (!args) { return cb(new Error('args required')); }
>> if (!args.id) { return cb(new Error('args.id required')); }
>>
>> SomeDatabase.get({id: args.id}, cb);
>> }
>>
>> What are the potential issues with not wrapping those arg checks in
>> process.nextTick()?
>>
>>
>> Thanks,
>>
>> Bryan
>>
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