Comments on: Tips for Programming JavaScript Functions

By: Zach Leatherman

Zach Leatherman — Wed, 16 Apr 2008 23:39:58 +0000

You’re right, I didn’t word that correctly.

I think it should say:
“It’s easier to use arg1 such that if you pass in a value, it should be true, or at least evaluate to true. Passing in false or null should be treated identically for coding that’s easier on the brain.”

Point well taken though.

By: Alexei M

Alexei M — Wed, 16 Apr 2008 15:08:14 +0000

“Don’t ever use arg1 in a way that would have you passing in false, because false and null are the same in a boolean comparison.”

Dude, there are lots of times when an empty string is a perfectly acceptable value and does not designate the absence of the parameter. If you check against undefined you don’t have to worry about this.

I ran into a very similar issue recently where I was checking for browser functionality like this:

var text = (el.textContent ? el.textContent : el.innerText);

The fix, depending on your tolerance for obfuscation, is either

var text = (el.textContent !== undefined ? el.textContent : el.innerText);

var text = el.textContent || el.innerText || ”.

By: Zach Leatherman

Zach Leatherman — Sat, 29 Mar 2008 14:50:39 +0000

Absolutely, that’s a good one too. For the non-computer scientists out there, that’s a method called short circuit evaluation.

By: kangax

kangax — Sat, 29 Mar 2008 06:23:59 +0000

I find myself using alternative syntax quite often:

runDoSomething && doSomething();