Comment by phamilton

"if (my_var != null)" Throws a reference error if my_var is not defined. By checking the typeof it will short-circuit before throwing the error. It is accepted enough to be the default coffeescript implementation of "?" (the existential operator).

The OPs point wasn't that you couldn't write faster code with non-blocking I/O. His point was that just having non-blocking I/O isn't always going to make things faster. Sure, most applications get lucky and have faster implementations, but it is important to understand what is happening behind the scenes in order to avoid hanging yourself. He thinks the Node.js community has not emphasized that understanding at all and the hype around Node.js is leading to badly written applications.