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.
![Regular Expressions for the Rest of Us]()
Sooner or later you'll run across a regular expression. With their cryptic syntax, confusing documentation and massive learning curve, most developers settle for copying and pasting them from StackOverflow and hoping they work. But what if you could decode regular expressions and harness their power? In...
![5 More HTML5 APIs You Didn’t Know Existed]()
The HTML5 revolution has provided us some awesome JavaScript and HTML APIs. Some are APIs we knew we've needed for years, others are cutting edge mobile and desktop helpers. Regardless of API strength or purpose, anything to help us better do our job is a...
![Introducing MooTools NextPrev]()
One thing I love doing is duplicating OS functionalities. One of the things your OS allows you to do easily is move from one item to another. Most of the time you're simply trying to get to the next or the previous item.
![Custom Scrollbars in WebKit]()
Before each of the browser vendors we like was providing unique CSS controls, Internet Explorer was setting the tone. One such example is IE's early implementation of CSS filters. Internet Explorer was also the first browser that allowed developers to, for better or worse, customize...
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.