             this.source = source == null ? [] : source;
         }
 
-
-        /*
-         * Extended part
-         * -------------------------------------------
-         */
-
+        /**
+         * Creates a new stream for all items that are not strictly equal to undefined (item !== <i>undefined</i>).
+         * @return A new stream that contains all items from the original stream that are not equal to <i>undefined</i>.
+         */
         public function compact():Stream
         {
             return filter(defined(_));

            source[5] = item;
        }

        public function get seventh():*
        {
            return source[6];

            source[8] = item;
        }

        /**
         * The tenth item of the stream
         */
        public function get tenth():*
        {
            return source[9];
