Question

YUI Compressor, in its (not very extensive) documentation states this as an option:

--disable-optimizations     Disable all the built-in micro optimizations. 

Does anyone know what this means?
What will this turn on/off?
I haven’t found any documentation about it.

Thanks!

Answer 1

Looking at the source of JavaScriptCompressor:

lines 548–

    if (!disableOptimizations) {         optimizeObjectMemberAccess(this.tokens);         optimizeObjLitMemberDecl(this.tokens);     } 

lines 467 –

/* * Transforms obj['foo'] into obj.foo whenever possible, saving 3 bytes. */ private static void optimizeObjectMemberAccess(ArrayList tokens) { 

lines 497 –

/*  * Transforms 'foo': ... into foo: ... whenever possible, saving 2 bytes.  */ private static void optimizeObjLitMemberDecl(ArrayList tokens) { 

So it’s converting use of constant strings in foo['bar'] to foo.bar and {'bar':x} to {bar:x}.