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!
![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...
![Detect DOM Node Insertions with JavaScript and CSS Animations]()
I work with an awesome cast of developers at Mozilla, and one of them in Daniel Buchner. Daniel's shared with me an awesome strategy for detecting when nodes have been injected into a parent node without using the deprecated DOM Events API.
![Duplicate DeSandro’s CSS Effect]()
I recently stumbled upon David DeSandro's website when I saw a tweet stating that someone had stolen/hotlinked his website design and code, and he decided to do the only logical thing to retaliate: use some simple JavaScript goodness to inject unicorns into their page.
![Link Nudging with CSS3 Animations]()
One of the more popular and simple effects I've featured on this blog over the past year has been linking nudging. I've created this effect with three flavors of JavaScript: MooTools, jQuery, and even the Dojo Toolkit. Luckily CSS3 (almost) allows us to ditch...
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