Fix <ComponentTabs> to display only the selected tab, not the other way around

Signed-off-by: Oliver Sand <oliver.sand@sda-se.com>

.changeset/two-foxes-marry.md

@@ -0,0 +1,5 @@
+---
+'@backstage/plugin-home': patch
+---
+
+Fix `<ComponentTabs>` to display only the selected tab, not the other way around.

plugins/home/src/componentRenderers/ComponentTabs/ComponentTabs.test.tsx

@@ -0,0 +1,76 @@
+/*
+ * Copyright 2021 The Backstage Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { render } from '@testing-library/react';
+import userEvent from '@testing-library/user-event';
+import React from 'react';
+import { ComponentTabs } from './ComponentTabs';
+
+describe('<ComponentTabs>', () => {
+  test('should render tabs without exploding', () => {
+    const { getByText } = render(
+      <ComponentTabs
+        title="Random Jokes"
+        tabs={[
+          {
+            label: 'TabA',
+            Component: () => <>ContentA</>,
+          },
+          {
+            label: 'TabB',
+            Component: () => <>ContentB</>,
+          },
+        ]}
+      />,
+    );
+
+    expect(getByText('TabA')).toBeInTheDocument();
+    expect(getByText('TabB')).toBeInTheDocument();
+
+    expect(getByText('ContentA')).toBeInTheDocument();
+    expect(getByText('ContentB')).toHaveStyle({
+      display: 'none',
+    });
+  });
+
+  test('should switch tab on click', () => {
+    const { getByText } = render(
+      <ComponentTabs
+        title="Random Jokes"
+        tabs={[
+          {
+            label: 'TabA',
+            Component: () => <>ContentA</>,
+          },
+          {
+            label: 'TabB',
+            Component: () => <>ContentB</>,
+          },
+        ]}
+      />,
+    );
+
+    expect(getByText('ContentB')).toHaveStyle({
+      display: 'none',
+    });
+
+    userEvent.click(getByText('TabB'));
+
+    expect(getByText('ContentA')).toHaveStyle({
+      display: 'none',
+    });
+  });
+});

plugins/home/src/componentRenderers/ComponentTabs/ComponentTabs.tsx

@@ -44,7 +44,10 @@ export const ComponentTabs = ({
         ))}
       </Tabs>
       {tabs.map(({ Component }, idx) => (
-        <div {...(idx === value ? { style: { display: 'none' } } : {})}>
+        <div
+          key={idx}
+          {...(idx !== value ? { style: { display: 'none' } } : {})}
+        >
           <Component />
         </div>
       ))}