Ticket #2616: map.diff

core.js

@@ -1189 +1189 @@
         return ret;
     },
 
-    map: function( elems, callback ) {
-        var ret = [];
+    map: function( source, callback, target ) {
+        if( !target )
+            target = 'length' in source ? [ ] : { };
+        
+        if( 'length' in target ){ //is it an array(-like) ? else a hash
+            var arr = true;
+            if( !target.concat )//fix array-like objects, or they will fail the final concat
+                target = jQuery.makeArray(target);
+        }
 
-        // Go through the array, translating each of the items to their
+        // Go through the items, translating each of them to their
         // new value (or values).
-        for ( var i = 0, length = elems.length; i < length; i++ ) {
-            var value = callback( elems[ i ], i );
+        jQuery.each( source , function( key, value ){
+            value = callback( value, key );
+            
+            if ( value != null )
+                target[ arr ? target.length : key ] = value;
+        });
 
-            if ( value !== null && value != undefined ) {
-                if ( value.constructor != Array )
-                    value = [ value ];
-
-                ret = ret.concat( value );
-            }
-        }
-
-        return ret;
+        //Array.concat can receive arrays and non-arrays too
+        return arr ? target.concat.apply( [], target ) : target;
     }
 });