Generate more compessor-friendly javascript

[dimzon]

Wrap class definitions into anonimous functions and use variables instead fully qualified

(function(){
...
  var _$$System$Drawing$Bitmap$prototype = System.Drawing.Bitmap.prototype;
  _$$System$Drawing$Bitmap$prototype._ctor$1 = function (filename, b) {
    _$$System$Drawing$Bitmap$prototype._ctor$0.call(this, filename);
  };
...
})();

[kg]

How does that help compressors specifically? It looks like the resulting JS would be larger and more complicated, so I don't know how that would help the compressor. Is there a specific compressor that struggles with the way the code works now so I can take a look?

[dimzon]

Google Closure Compiler, Yahoo Compressor and other good compressors can rename local variables and parameters (_$$System$Drawing$Bitmap$prototype) to something one-letter:

(function(){
 ...
 var a = System.Drawing.Bitmap.prototype;
 a._ctor$1 = function (x, b) {
 a._ctor$0.call(this, x);
 };
 ...
 })();

So You can use long significant names for local variables (to maintain readability) BUT compiler will optimize it reducing javascript size a lot.

the best way is to make JSIL.MakeClass to return a function itselt so you can generate something like this

//Trick: using unassigned parameter instead local variable definition (,v instead var v will save some chars)
(function(_$$System$Drawing$Bitmap,_$$System$Drawing$Bitmap$prototype){
_$$System$Drawing$Bitmap$prototype=_$$System$Drawing$Bitmap.prototype;
// Class definition below
 _$$System$Drawing$Bitmap$prototype._ctor$1 = function (filename, b) {
 _$$System$Drawing$Bitmap$prototype._ctor$0.call(this, filename);
 };
})(JSIL.MakeClass(.....));

[dimzon]

other trick is to use object['field'] instead of object.field notation
look at this sample

1. unoptimized original code

obj.prototype.foo=....;
obj.prototype.bar=....;
obj.prototype.aaa=...;

2. prepared code

var $prototype='prototype'; // must be LOCAL variable
obj[$prototype].foo=....;
obj[$prototype].bar=....;
obj[$prototype].aaa=...;

3. prepared after compilation (LOCAL variable names will be shortened to 1 char)

var p='prototype'; // must be LOCAL variable 
obj[p].foo=....;
obj[p].bar=....;
obj[p].aaa=...;

this trick works great if you combine whole assembly definition into one anonimous function and apply this trick for wide-used "apply" "call" "prototype" etc