On 7/26/16, 1:40 AM, "Harbs" <[email protected]> wrote:
>I noticed a couple of things:
>1. There’s lots of String(val) casts in FlexJS code. This practice is
>considered “bad” practice in Javascript where implicit conversion is
>generally quicker. So in a case where a number can be converted
>implicitly, the cast should be completely skipped and even when a number
>needs to be converted to a string, “” + val is more efficient than
>String(val). This is especially true in FlexJS where (I believe) such
>code will result in org.apache.flex.Language.as(val,”String”).
I'm not seeing this. What source code is generating String(val) calls?
Regarding optimization, do we know if GCC will do this ("" + val)
optimization for us?
In general, there is a big TODO around type conversions.
>
>2. String concatenation: I’m not sure how much of an issue this is in
>current browsers, but using aray.join() to build a string was MUCH faster
>than building strings using the plus operator. For longer strings the
>difference was dramatic.
If I understood this, it would be hard for the compiler to generate the
right code for all browsers. You could create a StringBuilder class that
checks platforms and runs different code at runtime.
FWIW, Flex UIDUtils uses ByteArray because, IIRC, while array.join() might
be fast, the array.push() is horribly slow and generates a lot of GC
activity.
HTH,
-Alex
