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 @supports]()
Feature detection via JavaScript is a client side best practice and for all the right reasons, but unfortunately that same functionality hasn't been available within CSS. What we end up doing is repeating the same properties multiple times with each browser prefix. Yuck. Another thing we...
![CSS 3D Folding Animation]()
Google Plus provides loads of inspiration for front-end developers, especially when it comes to the CSS and JavaScript wonders they create. Last year I duplicated their incredible PhotoStack effect with both MooTools and pure CSS; this time I'm going to duplicate...
![Animated AJAX Record Deletion Using MooTools]()
I'm a huge fan of WordPress' method of individual article deletion. You click the delete link, the menu item animates red, and the item disappears. Here's how to achieve that functionality with MooTools JavaScript.
The PHP - Content & Header
The following snippet goes at the...
![Hot Effect: MooTools Drag Opacity]()
As you should already know, the best visual features of a website are usually held within the most subtle of details. One simple trick that usually makes a big different is the use of opacity and fading. Another awesome MooTools functionality is...
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