Important performance improvement

[dimi]

While investigating poor .trim() performance, I discovered that there are only 2 places in core where trim() is used.

One place only needs to test if a string is blank, which can be done a *lot* faster than trimming. As a result this current patch does the following:

• adds a new .blank() function to core that test for empty string.
• uses the new function where appropriate to eliminate the .trim() function.

In my tests with a 660K string I got the following numbers:

.trim() .blank()

FF2/Linux 2353ms 9ms FF3/Windows 1571ms 8ms

At a very fundamental level .blank() is a much easier function to implement, does not require any memory allocation, and as a result I think it should be part of the core so others can make use of it. Moreover it only adds a tiny bit of code, basically just a few bytes.

That is, the minified code is only 47 bytes bigger. When gzipes, that drops to only 18bytes. This is a tiny price to pay for a >100x speedup in some cases.

[dimi]

Patch implementing the .blank() function.

[dimi]

Smaller, much faster version of .blank()

[dimi]

Read all about it here: ​http://zipalong.com/blog/?p=287

[john]

Fixed in SVN rev [6189]. I didn't add the .blank() method - that's something that we can explore later on.