The YUI compressor does not seem complain about using the Function
technique.
(function(){
function evaluate( data ){
return Function("return "+( data ) )();
};
})();
becomes...
(function(){function A(B){return Function("return "+(B))()}})();
On May 20, 9:06 am, John Resig <jere...@gmail.com> wrote:
> Has anyone been able to figure out if YUIMin still behaves as you would
> expect it to?
>
> --John
>
> On Wed, May 20, 2009 at 6:48 AM, Andrea Giammarchi <
>
> andrea.giammar...@gmail.com> wrote:
> > Ok, the reason eval is so slow is because of FireBug, it costed 17 seconds
> > with FireBug enabled while FireBug seems to do not affect Function execution
> > (which makes Function against better than eval).
>
> > In any case, Function is faster or exactly fast as eval is, even in
> > Internet Explorer, at least in my tests.
>
> > this is a truly simple readapted test case:
>
> > <!DOCTYPE html>
> > <script type="text/javascript">
> > portable = (function(msg, i, interval){
> > function timeout(){
> > alert(msg.join("\n"));
> > msg = [];
> > i = 0;
> > };
> > return {
> > log:function(test){
> > msg[i++] = test;
> > clearTimeout(interval);
> > interval = setTimeout(timeout, 100);
> > }
> > }
> > })([], 0, 0);
> > var count = 10000, o = null, i = 0, jsonString =
> > '{"value":{"items":[{"x":1,"y":2,"z":3},{"x":1,"y":2,"z":3},{"x":1,"y":2,"z":3},{"x":1,"y":2,"z":3},{"x":1,"y":2,"z":3}]},"error":null}';
> > var beginTime = new Date();
> > for ( i = 0; i < count; i++ )
> > o = eval( "(" + jsonString + ")" );
> > portable.log( "eval:" + ( new Date() - beginTime ) );
> > var beginTime = new Date();
> > for ( i = 0; i < count; i++ )
> > o = new Function( "return " + jsonString )();
> > portable.log( "new Function:" + ( new Date() - beginTime ) );
> > var beginTime = new Date();
> > for ( i = 0; i < count; i++ )
> > o = Function( "return " + jsonString )();
> > portable.log( "Function:" + ( new Date() - beginTime ) );
> > var beginTime = new Date();
> > var callback = Function( "return " + jsonString );
> > for ( i = 0; i < count; i++ )
> > o = callback();
> > portable.log( "precompiled Function:" + ( new Date() - beginTime ) );
> > if(this.JSON){
> > var beginTime = new Date();
> > for ( i = 0; i < count; i++ )
> > o = JSON.parse(jsonString);
> > portable.log( "native:" + ( new Date() - beginTime ) );
> > };
> > </script>
>
> > Let me know what you think.
>
> > Regards
>
> > On Wed, May 20, 2009 at 7:43 AM, Andrea Giammarchi <
> > andrea.giammar...@gmail.com> wrote:
>
> >> As I said, Function does not do scope resolution except the global one so
> >> in my opinion should be always preferred for JSON evaluations. Firefox does
> >> not care about implicit returned value plus brackets plus scope, it simply
> >> create the anonimous function doing a syntax check and returns errors only
> >> at call time so if there are no errors the precompiled funcion will be like
> >> a manual one, time for parsing syntax is then one against every eval call.
> >> To be fair, that bench make sense declaring the function once and simply
> >> calling it inside the for to always return the same object. Unfortunately
> >> this is not a real world case.
>
> >> On May 20, 2009 7:33 AM, "Michael Geary" <m...@mg.to> wrote:
>
> >> Function( 'return ' + data )() is also MUCH faster in Firefox than eval.
>
> >> In a test case of JSON data containing 1000 names and addresses (about
> >> 112KB), eval() takes a full second to execute on my machine in Firefox 3.
> >> On
> >> all other browsers (including IE!) it takes hardly any time at all.
>
> >> The Function version takes essentially no time in Firefox. (Didn't test it
> >> in other browsers.)
>
> >> -Mike
>
> >> ------------------------------
> >> *From:* jquery-dev@googlegroups.com [mailto:jquery-...@googlegroups.com]
> >> *On Behalf Of *John Resig
> >> *Sent:* Tuesday, May 19, 2009 4:20 PM
> >> *To:* jquery-dev@googlegroups.com
> >> *Subject:* [jquery-dev] Re: window['eval']() in rhino
>
> >> > I don't remember the original discussion/change, off-hand. If YUIMin is
> >> still able to generate an ...
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