Question

What’s better? If:

function a(){};

then is it faster to process this

if(typeof a == "function"){func(arg);}

or this?

if(!(typeof a).search("f")){func(arg);}

I’m only asking this because in my opinion its easier to match first symbol of string than entire string, no? Interested in making sure.

Answer 1

Here is a jsPerf test http://jsperf.com/typeof-test12.

• Your first code chunk: 527,021,419 operations per second.
• Your second code chunk: 9,803,840 operations per second.

That is a huge margin (the first one is 54 times faster than the second on my computer).