to save more space, compact version entirely based on NaN trick:
function myBestTrim( str ){
var start = -1, end = str.length;
while(str.charCodeAt( --end ) < 33);
while(str.charCodeAt( ++start ) < 33);
return str.slice( start, end + 1 );
};
Thoughts?
On Tue, Nov 4, 2008 at 10:00 PM, Andrea Giammarchi <
[EMAIL PROTECTED]> wrote:
> 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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