this.inserted = function()

in src/Clients/Web/winjs/js/winjs.js [29806:29899]
50 lines of code
30 McCabe index (conditional complexity)

                    this.inserted = function (newItem, previousKey, nextKey, index) {
                        /// <signature helpKeyword="WinJS.UI.VirtualizedDataSource.ListDataNotificationHandler.inserted">
                        /// <summary locid="WinJS.UI.VirtualizedDataSource.ListDataNotificationHandler.inserted">
                        /// Raises a notification that an item was inserted.
                        /// </summary>
                        /// <param name="newItem" type="Object" locid="WinJS.UI.VirtualizedDataSource.ListDataNotificationHandler.inserted_p:newItem">
                        /// The inserted item. It must have a key and a data property (it must implement the IItem interface).
                        /// </param>
                        /// <param name="previousKey" mayBeNull="true" type="String" locid="WinJS.UI.VirtualizedDataSource.ListDataNotificationHandler.inserted_p:previousKey">
                        /// The key of the item before the insertion point, or null if the item was inserted at the start of the
                        /// list.  It can be null if you specified nextKey.
                        /// </param>
                        /// <param name="nextKey" mayBeNull="true" type="String" locid="WinJS.UI.VirtualizedDataSource.ListDataNotificationHandler.inserted_p:nextKey">
                        /// The key of the item after the insertion point, or null if the item was inserted at the end of the list.
                        /// It can be null if you specified previousKey.
                        /// </param>
                        /// <param name="index" optional="true" type="Number" integer="true" locid="WinJS.UI.VirtualizedDataSource.ListDataNotificationHandler.inserted_p:index">
                        /// The index of the inserted item.
                        /// </param>
                        /// </signature>

                        if (editsQueued) {
                            // We can't change the slots out from under any queued edits
                            beginRefresh();
                        } else {
                            var key = newItem.key,
                                slotPrev = keyMap[previousKey],
                                slotNext = keyMap[nextKey];

                            var havePreviousKey = typeof previousKey === "string",
                                haveNextKey = typeof nextKey === "string";

                            // Only one of previousKey, nextKey needs to be passed in
                            //
                            if (havePreviousKey) {
                                if (slotNext && !slotNext.firstInSequence) {
                                    slotPrev = slotNext.prev;
                                }
                            } else if (haveNextKey) {
                                if (slotPrev && !slotPrev.lastInSequence) {
                                    slotNext = slotPrev.next;
                                }
                            }

                            // If the VDS believes the list is empty but the data adapter believes the item has
                            // a adjacent item start a refresh.
                            //
                            if ((havePreviousKey || haveNextKey) && !(slotPrev || slotNext) && (slotsStart.next === slotListEnd)) {
                                beginRefresh();
                                return;
                            }

                            // If this key is known, something has changed, start a refresh.
                            //
                            if (keyMap[key]) {
                                beginRefresh();
                                return;
                            }

                            // If the slots aren't adjacent or are thought to be distinct sequences by the
                            //  VDS something has changed so start a refresh.
                            //
                            if (slotPrev && slotNext) {
                                if (slotPrev.next !== slotNext || slotPrev.lastInSequence || slotNext.firstInSequence) {
                                    beginRefresh();
                                    return;
                                }
                            }

                            // If one of the adjacent keys or indicies has only just been requested - rare,
                            //  and easier to deal with in a refresh.
                            //
                            if ((slotPrev && (slotPrev.keyRequested || slotPrev.indexRequested)) ||
                                (slotNext && (slotNext.keyRequested || slotNext.indexRequested))) {
                                beginRefresh();
                                return;
                            }

                            if (slotPrev || slotNext) {
                                insertNewSlot(key, newItem, (slotNext ? slotNext : slotPrev.next), !!slotPrev, !!slotNext);
                            } else if (slotsStart.next === slotListEnd) {
                                insertNewSlot(key, newItem, slotsStart.next, true, true);
                            } else if (index !== undefined) {
                                updateNewIndicesFromIndex(index, 1);
                            } else {
                                // We could not find a previous or next slot and an index was not provided, start a refresh
                                //
                                beginRefresh();
                                return;
                            }

                            completeNotification();
                        }
                    };