jQuery.map to conform with style guidelines - improved size/DRY code

src/core.js

@@ -706,29 +706,31 @@ jQuery.extend({
 
 	// arg is for internal usage only
 	map: function( elems, callback, arg ) {
-		var ret = [],
-			value,
+		var ret = [], value, i = 0,
 			length = elems.length,
 			// same object detection used in jQuery.each, not full-proof but very speedy.
 			isObj = length === undefined;
-
-		if ( isObj ) {
-			for ( key in elems ) {
-				value = callback( elems[ key ], key, arg );
-
+			
+			// the work for the loops - run elems[x] through callback
+			inLoop = function( key ) {
+			  value = callback( elems[ key ], key, arg );
+			  
 				if ( value != null ) {
 					ret[ ret.length ] = value;
 				}
 			}
-		} else {
-			// Go through the array, translating each of the items to their
-			// new value (or values).
-			for ( var i = 0; i < length; i++ ) {
-				value = callback( elems[ i ], i, arg );
 
-				if ( value != null ) {
-					ret[ ret.length ] = value;
-				}
+    // Go thorugh every key on the object
+		if ( isObj ) {
+			for ( key in elems ) {
+			  inLoop( key );
+			}
+		
+		// Go through the array, translating each of the items to their
+		// new value (or values).
+		} else {			
+			for ( ; i < length; i++ ) {
+				inLoop( i );
 			}
 		}