I write a lot of JavaScript and I'm not even sure this is preferable. The "object wrappers" like String are considered deprecated in some circles as a matter of style, e.g. by Crockford. From this point of view, a stricter check is cleaner. And contrary to what the article implies, String(foo) is a cast to a primitive string, and doesn't create an object like 'new String' does.

So the Google function correctly returns whether String(foo) is a no-op.