Last suggestion.
The charCodeAt(--end) returns NaN when end is negative, and NaN < 33 is
false.
We can use this trick on start variable as well, removing one check for each
character.
As summary, I wonder which performances could have this version:
function myBestTrim( str ){
var start = -1, end;
if(end = str.length){
while(str.charCodeAt( --end ) < 33);
while(str.charCodeAt( ++start ) < 33);
str = str.slice( start, end + 1 );
};
return str;
};
Which seems to work fine for me.
Regards.
On Tue, Nov 4, 2008 at 9:44 PM, Andrea Giammarchi <
[EMAIL PROTECTED]> wrote:
> P.S.2 ... in php for example ++$var is a bit faster than $var++ , dunno in
> JS which one performs better, that was the other improvement that is true in
> my old laptop
>
>
> On Tue, Nov 4, 2008 at 9:42 PM, Andrea Giammarchi <
> [EMAIL PROTECTED]> wrote:
>
>> P.S. there is a logic problem, and probably a performances improvement
>> using ++start instead of start++
>>
>> function myBestTrim( str ){
>>
>> var start = -1,
>>
>> end = str.length;
>>
>> while(str.charCodeAt(--end) < 33);
>>
>> while(*++start* < end && str.charCodeAt(start) < 33);
>>
>> return str.slice( start, end + 1 );
>>
>> };
>>
>> In your code start++ is obviously less than end since value === 0 for the
>> first case will be true only on right side, the charCodeAt
>>
>> I know it was just a silly error and just one more boolean evaluation that
>> does not make that difference, but why do not fix it ;-)
>>
>>
>> On Tue, Nov 4, 2008 at 9:34 PM, Andrea Giammarchi <
>> [EMAIL PROTECTED]> wrote:
>>
>>> Ariel,
>>> I read now the myBestTrim function.
>>>
>>> You check charCodeAt less than 33, but in the precedent version you used
>>> these chars:
>>> chars = '
>>> \n\r\t\v\f\u00a0\u2000\u2001\u2002\u2003\u2004\u2005\u2006\u2007\u2008\u2009\u200a\u200b\u2028\u2029\u3000';
>>>
>>> I wonder which side effect could we have ignoring thos u2XXX characters,
>>> that as far as I know, are not included in range 0, 33 ... am I wrong?
>>>
>>> On Tue, Nov 4, 2008 at 9:28 PM, Andrea Giammarchi <
>>> [EMAIL PROTECTED]> wrote:
>>>
>>>>
>>>>
>>>> On Tue, Nov 4, 2008 at 5:58 PM, Ariel Flesler <[EMAIL PROTECTED]>wrote:
>>>>
>>>>>
>>>>> P.S: I knew you'd be throwin' in your super revolutionary version of
>>>>> it.. so predictable :-P
>>>>
>>>>
>>>> :D
>>>>
>>>> mine was just a suggestion. Clever or recent browsers cast as constant
>>>> the regexp, but to be sure it happens everywhere, you can "force" in that
>>>> way.
>>>>
>>>> My point is that I still cannot believe a runtime code works faster than
>>>> a regexp that should perform exactly the same in core. This could depend on
>>>> regexp engine, but we are still talking about compiled C against runtime
>>>> interpretated code (unless we are not under V8, TraceMonkey, or
>>>> SquirrelFish
>>>> Extreme)
>>>>
>>>> In any case, I tested the same over this string: Array(1000).join(" test
>>>> ") and you are right, your performs in a reasonable time, while the RegExp,
>>>> casted or not, asks me to stop the script execution.
>>>> This is hilarius to me, and I can think about a regexp engine problem
>>>> more than a bad practice, so I guess your porposal makes sense enough,
>>>> since
>>>> it is a must for big strings, a little bit slower for small strings.
>>>>
>>>> Cheers
>>>>
>>>
>>>
>>
>
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