feat(theme-classic): allow passing additional attributes to tab headings

packages/docusaurus-theme-classic/src/theme-classic.d.ts

@@ -514,6 +514,7 @@ declare module '@theme/TabItem' {
     readonly label?: string;
     readonly hidden?: boolean;
     readonly className?: string;
+    readonly attributes?: Record<string, unknown>;
   }
 
   const TabItem: (props: Props) => JSX.Element;
@@ -529,7 +530,11 @@ declare module '@theme/Tabs' {
     readonly block?: boolean;
     readonly children: readonly ReactElement<TabItemProps>[];
     readonly defaultValue?: string | null;
-    readonly values?: readonly {value: string; label?: string}[];
+    readonly values?: readonly {
+      value: string;
+      label?: string;
+      attributes?: Record<string, unknown>;
+    }[];
     readonly groupId?: string;
     readonly className?: string;
   }

packages/docusaurus-theme-classic/src/theme/Tabs/index.tsx

@@ -51,7 +51,13 @@ function TabsComponent(props: Props): JSX.Element {
     );
   });
   const values =
-    valuesProp ?? children.map(({props: {value, label}}) => ({value, label}));
+    valuesProp ??
+    // We only pick keys that we recognize. MDX would inject some keys by default
+    children.map(({props: {value, label, attributes}}) => ({
+      value,
+      label,
+      attributes,
+    }));
   const dup = duplicates(values, (a, b) => a.value === b.value);
   if (dup.length > 0) {
     throw new Error(
@@ -144,19 +150,25 @@ function TabsComponent(props: Props): JSX.Element {
           },
           className,
         )}>
-        {values.map(({value, label}) => (
+        {values.map(({value, label, attributes}) => (
           <li
             role="tab"
             tabIndex={selectedValue === value ? 0 : -1}
             aria-selected={selectedValue === value}
-            className={clsx('tabs__item', styles.tabItem, {
-              'tabs__item--active': selectedValue === value,
-            })}
             key={value}
             ref={(tabControl) => tabRefs.push(tabControl)}
             onKeyDown={handleKeydown}
             onFocus={handleTabChange}
-            onClick={handleTabChange}>
+            onClick={handleTabChange}
+            {...attributes}
+            className={clsx(
+              'tabs__item',
+              styles.tabItem,
+              attributes?.className as string,
+              {
+                'tabs__item--active': selectedValue === value,
+              },
+            )}>
             {label ?? value}
           </li>
         ))}

website/docs/guides/markdown-features/markdown-features-tabs-styles.module.css

@@ -0,0 +1,27 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+.red {
+  color: red;
+}
+.red[aria-selected="true"] {
+  border-bottom-color: red;
+}
+
+.orange {
+  color: orange;
+}
+.orange[aria-selected="true"] {
+  border-bottom-color: orange;
+}
+
+.yellow {
+  color: yellow;
+}
+.yellow[aria-selected="true"] {
+  border-bottom-color: yellow;
+}

website/docs/guides/markdown-features/markdown-features-tabs.mdx

@@ -9,6 +9,7 @@ slug: /markdown-features/tabs
 import BrowserWindow from '@site/src/components/BrowserWindow';
 import Tabs from '@theme/Tabs';
 import TabItem from '@theme/TabItem';
+import styles from './markdown-features-tabs-styles.module.css';
 ```
 
 Docusaurus provides `<Tabs>` components that you can use thanks to [MDX](./markdown-features-react.mdx):
@@ -229,15 +230,12 @@ Tab choices with different `groupId`s will not interfere with each other:
 You might want to customize the appearance of certain set of tabs. To do that you can pass the string in `className` prop and the specified CSS class will be added to the `Tabs` component:
 
 ```jsx
-import Tabs from '@theme/Tabs';
-import TabItem from '@theme/TabItem';
-
 // highlight-next-line
 <Tabs className="unique-tabs">
   <TabItem value="Apple">This is an apple 🍎</TabItem>
   <TabItem value="Orange">This is an orange 🍊</TabItem>
   <TabItem value="Banana">This is a banana 🍌</TabItem>
-</Tabs>;
+</Tabs>
 ```
 
 ```mdx-code-block
@@ -249,3 +247,76 @@ import TabItem from '@theme/TabItem';
   </Tabs>
 </BrowserWindow>
 ```
+
+### Customizing tab headings
+
+You can also customize each tab heading independently by using the `attributes` field. The extra props can be passed to the headings either through the `values` prop in `Tabs`, or props of each `TabItem`—in the same way as you declare `label`.
+
+<!-- prettier-ignore-start -->
+```jsx title="some-doc.mdx"
+import styles from './styles.module.css';
+
+<Tabs>
+  <TabItem value="apple" label="Apple" attributes={{className: styles.red}}>
+    This is an apple 🍎
+  </TabItem>
+  <TabItem value="orange" label="Orange" attributes={{className: styles.orange}}>
+    This is an orange 🍊
+  </TabItem>
+  <TabItem value="banana" label="Banana" attributes={{className: styles.yellow}}>
+    This is a banana 🍌
+  </TabItem>
+</Tabs>
+```
+<!-- prettier-ignore-end -->
+
+```css title="styles.module.css"
+.red {
+  color: red;
+}
+.red[aria-selected='true'] {
+  border-bottom-color: red;
+}
+
+.orange {
+  color: orange;
+}
+.orange[aria-selected='true'] {
+  border-bottom-color: orange;
+}
+
+.yellow {
+  color: yellow;
+}
+.yellow[aria-selected='true'] {
+  border-bottom-color: yellow;
+}
+```
+
+```mdx-code-block
+<BrowserWindow>
+  <Tabs>
+    <TabItem value="apple" label="Apple" attributes={{className: styles.red}}>
+      This is an apple 🍎
+    </TabItem>
+    <TabItem value="orange" label="Orange" attributes={{className: styles.orange}}>
+      This is an orange 🍊
+    </TabItem>
+    <TabItem value="banana" label="Banana" attributes={{className: styles.yellow}}>
+      This is a banana 🍌
+    </TabItem>
+  </Tabs>
+</BrowserWindow>
+```
+
+:::tip
+
+`className` would be merged with other default class names. You may also use a custom `data-value` field (`{'data-value': 'apple'}`) paired with CSS attribute selectors:
+
+```css title="styles.module.css"
+li[role='tab'][data-value='apple'] {
+  color: red;
+}
+```
+
+:::

website/src/components/BrowserWindow/styles.module.css

@@ -10,6 +10,7 @@
   border-top-left-radius: var(--ifm-global-radius);
   border-top-right-radius: var(--ifm-global-radius);
   box-shadow: var(--ifm-global-shadow-lw);
+  margin-bottom: var(--ifm-leading);
 }
 
 .browserWindowHeader {