Issue link: https://read.uberflip.com/i/1146286
The Savings | 71 As a demonstration, let's use these tools on event.js from the Yahoo! User Interface (YUI) library (http://developer.yahoo.com/yui). The source code for the first function follows: YAHOO.util.CustomEvent = function(type, oScope, silent, signature) { this.type = type; this.scope = oScope || window; this.silent = silent; this.signature = signature || YAHOO.util.CustomEvent.LIST; this.subscribers = []; if (!this.silent) { } var onsubscribeType = "_YUICEOnSubscribe"; if (type !== onsubscribeType) { this.subscribeEvent = new YAHOO.util.CustomEvent(onsubscribeType, this, true); } }; The same function passed through JSMin has all unneeded whitespace removed: YAHOO.util.CustomEvent=function(type,oScope,silent,signature){this.type=type;this. scope=oScope||window;this.silent=silent;this.signature=signature||YAHOO.util. CustomEvent.LIST;this.subscribers=[];if(!this.silent){} var onsubscribeType="_YUICEOnSubscribe";if(type!==onsubscribeType){this.subscribeEv ent=new YAHOO.util.CustomEvent(onsubscribeType,this,true);}}; Dojo Compressor removes most whitespace, but additionally shortens variable names. Notice how _1 has replaced type as the first parameter to the CustomEvent function: YAHOO.util.CustomEvent=function(_1,_2,_3,_4){ this.type=_1; this.scope=_2||window; this.silent=_3; this.signature=_4||YAHOO.util.CustomEvent.LIST; this.subscribers=[]; if(!this.silent){ } var _5="_YUICEOnSubscribe"; if(_1!==_5){ this.subscribeEvent=new YAHOO.util.CustomEvent(_5,this,true); } }; Table 10-2 shows some potential savings for the six companies who didn't minify their JavaScript files. I downloaded the JavaScript files used on each site's home page. The table shows the original size of each site's JavaScript files, as well as the size reductions gained by running them through JSMin and Dojo Compressor. On average, JSMin reduced the size of JavaScript files by 21%, while Dojo Compressor achieved a 25% reduction.