Comments on: RegExp In An Anonymous Function

By: jackson

jackson — Mon, 05 Oct 2009 16:25:49 +0000

This piqued my interest so I tried it out:

const ITERATIONS:int = 5000000;
var i:int;
var before:int = getTimer();
for (i = 0; i < ITERATIONS; ++i)
{
    /^monkey$/.exec("notmonkey");
}
trace("Special Syntax: " + (getTimer()-before));
 
before = getTimer();
for (i = 0; i < ITERATIONS; ++i)
{
    new RegExp("^monkey$").exec("notmonkey");
}
trace("Constructor: " + (getTimer()-before));

And the results:

Special Syntax: 8228
Constructor: 8228

So I guess it really is just syntax sugar.

By: dVyper

dVyper — Mon, 05 Oct 2009 08:12:22 +0000

I wonder if anyone has done any speed comparisons between using the RegExp constructor and not using it…

By: jackson

jackson — Sat, 03 Oct 2009 03:48:02 +0000

Good point. If you’re going to use the syntax sugar, you have a constant regular expression anyhow. Thanks for pointing this out.

By: Jan

Jan — Sat, 03 Oct 2009 03:42:59 +0000

This way very simple and clean:

public static const UPPER : RegExp = /[A-Z]/;
public static const LOWER : RegExp = /[a-z]/;

Usage:

UPPER.test(“Hello world”)

By: jackson

jackson — Fri, 02 Oct 2009 15:51:50 +0000

Whoa. It makes the syntax even weirder, but still a nice workaround so you can use the syntax sugar. Thanks for the tip!

By: hanamura

hanamura — Fri, 02 Oct 2009 11:22:20 +0000

This also works fine in my environment.

return (/^monkey$/);