As javascript is single threaded you usually don't need callback unless
it's IO related. However, there are exceptions:
(i) Heavy calculations might want to utilize process.nextTick() or
timeout, to avoid blocking. You would have to use a callback to return
the final results
(ii) Webworker results are passed as messages (not a return statement) so
inherently asynchronous, even when there is no "real" IO.
On Tuesday, April 9, 2013 7:10:12 PM UTC-4, Eldar wrote:
>
> No, you get it all wrong.
>
> Callbacks you use for `for-loops` (array.forEach() I guess) are not async
> at all.
>
> The forEach() method is actually nothing but:
>
> // simplified
> Array.prototype.forEach = function (cb) {
> for (var i = 0; i < this.length; i++) {
> cb(this[i])
> }
> }
>
> So it just performs iterating stuff for you and frees your hands from
> bothering with for loop.
>
> I strongly recommend you to stop writing any code and read good book about
> javaScript and
> functional programming in general.
>
> On Wednesday, April 10, 2013 2:02:44 AM UTC+4, Mil Werns wrote:
>>
>> I have a simple question: When should I use callbacks?
>>
>> Currently, I'm only using callbacks in I/O cases (file, database and
>> network access).
>> My application has to iterate over a lot of big arrays and combines this
>> data to new objects. I'm doing this with a standard (synchronous) for-loop,
>> because this task needs only CPU power. So there would be no benefit to use
>> an asynchronous call.
>>
>> Is this assumption correct?
>> Can you please give me other examples for useful callbacks other than
>> those mentioned above?
>>
>> Thank you
>>
>
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