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!
![Camera and Video Control with HTML5]()
Client-side APIs on mobile and desktop devices are quickly providing the same APIs. Of course our mobile devices got access to some of these APIs first, but those APIs are slowly making their way to the desktop. One of those APIs is the getUserMedia API...
![Conquering Impostor Syndrome]()
Two years ago I documented my struggles with Imposter Syndrome and the response was immense. I received messages of support and commiseration from new web developers, veteran engineers, and even persons of all experience levels in other professions. I've even caught myself reading the post...
![jQuery Countdown Plugin]()
You've probably been to sites like RapidShare and MegaUpload that allow you to download files but make you wait a specified number of seconds before giving you the download link. I've created a similar script but my script allows you to animate the CSS font-size...
![Add Styles to Console Statements]()
I was recently checking out Google Plus because they implement some awesome effects. I opened the console and same the following message:
WARNING!
Using this console may allow attackers to impersonate you and steal your information using an attack called Self-XSS.
Do not enter or paste code that you...
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