string casting speed in node.js/javascript

coerce.js

var a = 5,
    count = 100 * 1000 * 1000;

for (var i = 0; i < count; i++)
  ''+a;

String.js

var a = 5,
    count = 100 * 1000 * 1000;

for (var i = 0; i < count; i++)
  String(a);

toString.js

var a = 5,
    count = 100 * 1000 * 1000;

for (var i = 0; i < count; i++)
  a.toString();

Zoutput.md

String() constructor cast

dave @ [ bahamas10 :: (Darwin) ] ~/temp/benchmark $ time node String.js 

real	0m2.618s
user	0m2.613s
sys	0m0.017s

toString() cast

dave @ [ bahamas10 :: (Darwin) ] ~/temp/benchmark $ time node toString.js 

real	0m1.323s
user	0m1.315s
sys	0m0.013s

''+num cast (coercion)

dave @ [ bahamas10 :: (Darwin) ] ~/temp/benchmark $ time node coerce.js 

real	0m0.690s
user	0m0.681s
sys	0m0.011s

Coercing wins!