JavaScript Compression Alternatives to /packer/

Posted 2008-03-03 in JavaScript by Johann.

Squeezing the last bits out of your JavaScript files? Then you probably know /packer/. Maybe you even use it with YUI to automatically compress multiple JavaScripts into one file.

Recently, I discovered new alternatives to /packer/ and decided to compare them.

JavaScript compressors

The two new JavaScript crunchers I test are

• JSIntegration, a Java-based JavaScript packer with a Java Swing frontend. I used the JSA-20071021.jar file. My settings were: “Syntax compression” on, “text compression” on, “Compatible(IE5,NS3)” on, “auto confuse” off. The header comment was removed.
• JavaScript Utility V2 by Patrick J. O'Neil. I used the ISO-8859-1/UTF-8 setting.

Test files

The files I compressed were

1. The JavaScript for johannburkard.de. 73716 B uncompressed, 43170 B after YUI.
2. jQuery 1.2.3. 96763 B uncompressed, 53807 B after YUI.

I started with YUI compressed versions.

Results

johannburkard.de JavaScript

1. 23223 B (31 %) – JavaScript Utility
2. 25711 B (34 %) – JSA
3. 27988 B (38 %) – /packer/

jQuery 1.2.3

1. 25877 B (27 %) – JavaScript Utility
2. 28646 B (30 %) – JSA
3. 29606 B (31 %) – /packer/

Decompression times

While packed JavaScript files make your pages load faster, the browser still has to decompress the file. I didn’t benchmark all packers but the previous version of JavaScript Utility was about twice as slow as /packer/. After a recent update, JavaScript Utility is now about as fast as /packer/ (some informal performance numbers, OpenOffice document).

Edit: Neil Roberts suggested that I try ShrinkSafe instead of YUI. Here are the results:

johannburkard.de JavaScript

24689 B (33 %) – ShrinkSafe, then JavaScript Utility.

jQuery 1.2.3

27469 B (28 %) – ShrinkSafe, then JavaScript Utility.

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