[Discover] Move actions to utils

src/platform/packages/shared/kbn-unified-tabs/src/components/tabbed_content/tabbed_content.tsx

@@ -12,6 +12,7 @@ import { htmlIdGenerator, EuiFlexGroup, EuiFlexItem } from '@elastic/eui';
 import { TabsBar } from '../tabs_bar';
 import { getTabAttributes } from '../../utils/get_tab_attributes';
 import { getTabMenuActions } from '../../utils/get_tab_menu_actions';
+import { addTab, removeTab, selectTab } from '../../utils/manage_tabs';
 import { TabItem } from '../../types';
 
 export interface TabbedContentProps {
@@ -59,39 +60,21 @@ export const TabbedContent: React.FC<TabbedContentProps> = ({
 
   const onSelect = useCallback(
     (item: TabItem) => {
-      changeState((prevState) => ({
-        ...prevState,
-        selectedItem: item,
-      }));
+      changeState((prevState) => selectTab(prevState, item));
     },
     [changeState]
   );
 
   const onClose = useCallback(
     (item: TabItem) => {
-      changeState((prevState) => {
-        const nextItems = prevState.items.filter((prevItem) => prevItem.id !== item.id);
-        // TODO: better selection logic
-        const nextSelectedItem = nextItems.length ? nextItems[nextItems.length - 1] : null;
-
-        return {
-          items: nextItems,
-          selectedItem:
-            prevState.selectedItem?.id !== item.id ? prevState.selectedItem : nextSelectedItem,
-        };
-      });
+      changeState((prevState) => removeTab(prevState, item));
     },
     [changeState]
   );
 
   const onAdd = useCallback(() => {
     const newItem = createItem();
-    changeState((prevState) => {
-      return {
-        items: [...prevState.items, newItem],
-        selectedItem: newItem,
-      };
-    });
+    changeState((prevState) => addTab(prevState, newItem));
   }, [changeState, createItem]);
 
   const getTabMenuItems = useMemo(() => {

src/platform/packages/shared/kbn-unified-tabs/src/utils/manage_tabs.ts

@@ -0,0 +1,58 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the "Elastic License
+ * 2.0", the "GNU Affero General Public License v3.0 only", and the "Server Side
+ * Public License v 1"; you may not use this file except in compliance with, at
+ * your election, the "Elastic License 2.0", the "GNU Affero General Public
+ * License v3.0 only", or the "Server Side Public License, v 1".
+ */
+
+import type { TabItem } from '../types';
+
+interface TabsState {
+  items: TabItem[];
+  selectedItem: TabItem | null;
+}
+
+export const addTab = ({ items }: TabsState, item: TabItem): TabsState => {
+  return {
+    items: [...items, item],
+    selectedItem: item,
+  };
+};
+
+export const removeTab = ({ items, selectedItem }: TabsState, item: TabItem): TabsState => {
+  const itemIndex = items.findIndex((i) => i.id === item.id);
+
+  if (itemIndex === -1) {
+    return {
+      items,
+      selectedItem,
+    };
+  }
+
+  const nextItems = [...items];
+  nextItems.splice(itemIndex, 1);
+
+  if (selectedItem?.id !== item.id) {
+    return {
+      items: nextItems,
+      selectedItem,
+    };
+  }
+
+  const nextSelectedIndex = itemIndex === items.length - 1 ? itemIndex - 1 : itemIndex;
+  const nextSelectedItem = nextItems[nextSelectedIndex] || null;
+
+  return {
+    items: nextItems,
+    selectedItem: nextSelectedItem,
+  };
+};
+
+export const selectTab = ({ items, selectedItem }: TabsState, item: TabItem): TabsState => {
+  return {
+    items,
+    selectedItem: items.find((i) => i.id === item.id) || selectedItem,
+  };
+};