minify - Is there any point of using "return !0" in javascript?

Question

If you go to a google result page, and run rwt.toString(), you'll see that the return call for this function is:

return !0;

I can't think of any reason why this wouldn't always be true. Is this just a shorthand for true, or is there more going on here?

Answer 1

It is always true, but it takes 2 bytes to download (!0 is 2 characters) instead of 4 bytes to download the boolean value true.

Most Javascript minifiers will convert true to !0 and false to !1. You can see an example of this by typing var y = true; with Simple optimizations on Google's Closure Compiler: http://closure-compiler.appspot.com/home