Shaving Bytes with JavaScript Booleans
Developers are always search for ultimate way to create something with the least amount of code. This, of course, is one of the reasons we use minifiers: to serve code as small as possible. Of course this practice has numerous benefits, like faster download time, less storage consumption, etc. One way that minifiers are able to shave bytes off of JavaScript code is changing the way booleans are used.
true === !0 // Save 2 chars
false === !1 // Save 3 chars
A few bytes of every true and false go away with the ! evaluation. If you set one-letter variables names to those values, you may end up saving more. Keep in mind I'm not telling you to do this in your source code -- minifiers like Uglify JS will do this for you. Just something neat to know about though!
![CSS vs. JS Animation: Which is Faster?]()
How is it possible that JavaScript-based animation has secretly always been as fast — or faster — than CSS transitions? And, how is it possible that Adobe and Google consistently release media-rich mobile sites that rival the performance of native apps?
This article serves as a point-by-point...
![5 Ways that CSS and JavaScript Interact That You May Not Know About]()
CSS and JavaScript: the lines seemingly get blurred by each browser release. They have always done a very different job but in the end they are both front-end technologies so they need do need to work closely. We have our .js files and our .css, but...
![Save Text Size Preference Using MooTools 1.2]()
Last time posting here I taught you how to change text-size with JavaScript. The problem with using the solution I presented as Ian Lloyd pointed out:
Increase the font size, follow a link to another web page on same site and … back...
![Using MooTools to Instruct Google Analytics to Track Outbound Links]()
Google Analytics provides a wealth of information about who's coming to your website. One of the most important statistics the service provides is the referrer statistic -- you've gotta know who's sending people to your website, right? What about where you send others though?
Cool :-)
Glad you aren’t advocating coding like this directly. Can’t beat true/false for readability.
Coercions like
NumbertoBooleandoesn’t affect performance?Maybe too simple of a test: http://jsperf.com/bool-num-test
Looks like using
!0and!1may be faster (in Chrome 35) but only marginally.Even if that’s true, and it’s not due to some statistical error, the gain is so small it’s not really worth it.
Those are noops anyway. I would be surprised if the JS engine just optimise them away at compile time.
didn’t just*
Still prefer true/false for readability. As you said, it is better to let the Minifier to do this for us. It is better to keep the true/false in our code.
I expect the gain to be lost as soon as the file gets gzipped. I am wrong?
You should also remember the bitwise operations like
!~number, that returns true only for -1