Shaving Bytes on JavaScript Conditionals
Whenever you work with JavaScript code, it's as though there's always a shorter way to code something. You thought that a code set was basic until you found out that something was basic...er. One of those code shortcuts can be found with conditions, specifically short if clauses.
A typical short if clause would look something like this:
if(callback) {
callback();
}
Oddly enough this conditional can be made shorter:
callback && callback();
The && is less code than the if(){}; of course only by a few characters but does the same job. You could argue that readability suffers but that's up to individual developers.
![Write Better JavaScript with Promises]()
You've probably heard the talk around the water cooler about how promises are the future. All of the cool kids are using them, but you don't see what makes them so special. Can't you just use a callback? What's the big deal? In this article, we'll...
![CSS Gradients]()
With CSS border-radius, I showed you how CSS can bridge the gap between design and development by adding rounded corners to elements. CSS gradients are another step in that direction. Now that CSS gradients are supported in Internet Explorer 8+, Firefox, Safari, and Chrome...
![How to Create a Twitter Card]()
One of my favorite social APIs was the Open Graph API adopted by Facebook. Adding just a few META tags to each page allowed links to my article to be styled and presented the way I wanted them to, giving me a bit of control...
![Image Protection Using PHP, the GD Library, JavaScript, and XHTML]()
Warning: The demo for this post may brick your browser.
A while back I posted a MooTools plugin called dwProtector that aimed to make image theft more difficult -- NOT PREVENT IT COMPLETELY -- but make it more difficult for the rookie to average user...
It’s worth noting that JS minifiers like Google’s Closure Compiler will do this for you, so the first option is probably better so you get the readability without sacrificing performance. The Closure Compiler outputs it as this:
callback&&callback();
http://closure-compiler.appspot.com/home
and also jshint might shout about the shorter version (depending on the settings of course).
No one writes code for JSHint :)
It’s bad practice though because the code is hard to maintain, debug and extend. I could write a whole blog on why doing this is bad. I see zero benefits.
Agree with comments above. I recently realized that there is no benefits of having expressions in my code so changed jshint settings and now it disallows to use them.
IMO the expression below is pretty readable and it also takes one line:
if (callback) callback();
Agree with the “bad practice” comments.
Sometimes you seem to post stuff just for the sake of it, or to impress beginners.
I appreciate your honesty but impressing people isn’t something that entertains me.
What if I also need to have an else branch?
There’s only “if”, I suppose. Otherwise it’s something like:
While I agree with people’s comments on code readability, I still appreciate posts like this.
I’ve come across the ‘callback && callback();’ syntax before and had to look up wtf was going on. Had I read this post earlier, I would’ve known :)
@Dan i agree with you, posts like this are handy so you understand when you come across it in a project. Sadly, this is clearly lost on a couple of the previous commenters who already know everything there is to know.
I’m not worried about them.
What setting will make jsHint happy?
Code is better than anything, 2 JsPerf :
– http://jsperf.com/if-statement-verses-and-operator
– http://jsperf.com/ternary-vs-and-or-vs-if-else
Readability is important, but for those who like to hyper-optimize their code, this is a great tip.