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!
![Responsive Images: The Ultimate Guide]()
Chances are that any Web designers using our Ghostlab browser testing app, which allows seamless testing across all devices simultaneously, will have worked with responsive design in some shape or form. And as today's websites and devices become ever more varied, a plethora of responsive images...
![9 More Mind-Blowing WebGL Demos]()
With Firefox OS, asm.js, and the push for browser performance improvements, canvas and WebGL technologies are opening a world of possibilities. I featured 9 Mind-Blowing Canvas Demos and then took it up a level with 9 Mind-Blowing WebGL Demos, but I want to outdo...
![Create WordPress Page Templates with Custom Queries]()
One of my main goals with the redesign was to make it easier for visitors to find the information that was most popular on my site. Not to my surprise, posts about MooTools, jQuery, and CSS were at the top of the list. What...
![Save Web Form Content Using Control + S]()
We've all used word processing applications like Microsoft Word and if there's one thing they've taught you it's that you need to save every few seconds in anticipation of the inevitable crash. WordPress has mimicked this functionality within their WYSIWYG editor and I use it...
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