From 0add8cc8ae888b7cf59394675e6edfb179d2f544 Mon Sep 17 00:00:00 2001
From: Akira Sudoh <asudoh@gmail.com>
Date: Fri, 17 Jan 2020 07:45:56 +0900
Subject: [PATCH] fix(Tabs): add ARIA attributes (#4970)

This change adds ARIA attributes to `<Tab>` and `<TabContent>` to
better describe their relationship.

Fixes #4968.
---
 packages/react/src/components/Tab/Tab.js      |  8 ++++++
 .../src/components/TabContent/TabContent.js   |  1 +
 .../react/src/components/Tabs/Tabs-story.js   | 26 +++++++++++++------
 packages/react/src/components/Tabs/Tabs.js    | 11 ++++++--
 4 files changed, 36 insertions(+), 10 deletions(-)

diff --git a/packages/react/src/components/Tab/Tab.js b/packages/react/src/components/Tab/Tab.js
index dde7ce38914a..ead5751e62c3 100644
--- a/packages/react/src/components/Tab/Tab.js
+++ b/packages/react/src/components/Tab/Tab.js
@@ -15,6 +15,11 @@ const { prefix } = settings;
 
 export default class Tab extends React.Component {
   static propTypes = {
+    /**
+     * The element ID for the top-level element.
+     */
+    id: PropTypes.string,
+
     /**
      * Specify an optional className to be added to your Tab
      */
@@ -104,6 +109,7 @@ export default class Tab extends React.Component {
 
   render() {
     const {
+      id,
       className,
       handleTabClick,
       handleTabKeyDown,
@@ -126,12 +132,14 @@ export default class Tab extends React.Component {
     });
 
     const anchorProps = {
+      id,
       className: `${prefix}--tabs__nav-link`,
       href,
       role: 'tab',
       tabIndex: !disabled ? tabIndex : -1,
       ['aria-selected']: selected,
       ['aria-disabled']: disabled,
+      ['aria-controls']: id && `${id}__panel`,
       ref: e => {
         this.tabAnchor = e;
       },
diff --git a/packages/react/src/components/TabContent/TabContent.js b/packages/react/src/components/TabContent/TabContent.js
index 4d942191f72d..d190b844dac6 100644
--- a/packages/react/src/components/TabContent/TabContent.js
+++ b/packages/react/src/components/TabContent/TabContent.js
@@ -19,6 +19,7 @@ const TabContent = props => {
   });
   return (
     <div
+      role="tabpanel"
       {...other}
       className={tabContentClasses}
       selected={selected}
diff --git a/packages/react/src/components/Tabs/Tabs-story.js b/packages/react/src/components/Tabs/Tabs-story.js
index e49bdfbc7fbf..b1fe33167101 100644
--- a/packages/react/src/components/Tabs/Tabs-story.js
+++ b/packages/react/src/components/Tabs/Tabs-story.js
@@ -57,7 +57,9 @@ const TabContentRenderedOnlyWhenSelected = ({
   className,
   ...other
 }) =>
-  !selected ? null : (
+  !selected ? (
+    <div {...other} ciassName="bx--visually-hidden" />
+  ) : (
     <div
       {...other}
       className={classNames(className, `${prefix}--tab-content`)}
@@ -72,22 +74,26 @@ storiesOf('Tabs', module)
     'Default',
     () => (
       <Tabs {...props.tabs()}>
-        <Tab {...props.tab()} label="Tab label 1">
+        <Tab id="tab-1" {...props.tab()} label="Tab label 1">
           <div className="some-content">Content for first tab goes here.</div>
         </Tab>
-        <Tab {...props.tab()} label="Tab label 2">
+        <Tab id="tab-2" {...props.tab()} label="Tab label 2">
           <div className="some-content">Content for second tab goes here.</div>
         </Tab>
-        <Tab {...props.tab()} label="Tab label 3" disabled>
+        <Tab id="tab-3" {...props.tab()} label="Tab label 3" disabled>
           <div className="some-content">Content for third tab goes here.</div>
         </Tab>
         <Tab
+          id="tab-4"
           {...props.tab()}
           label="Tab label 4"
           renderContent={TabContentRenderedOnlyWhenSelected}>
           <div className="some-content">Content for fourth tab goes here.</div>
         </Tab>
-        <Tab {...props.tab()} label={<CustomLabel text="Custom Label" />}>
+        <Tab
+          id="tab-5"
+          {...props.tab()}
+          label={<CustomLabel text="Custom Label" />}>
           <div className="some-content">Content for fifth tab goes here.</div>
         </Tab>
       </Tabs>
@@ -105,19 +111,23 @@ storiesOf('Tabs', module)
     'Container',
     () => (
       <Tabs type="container" {...props.tabs()}>
-        <Tab {...props.tab()} label="Tab label 1">
+        <Tab id="tab-1" {...props.tab()} label="Tab label 1">
           <div className="some-content">Content for first tab goes here.</div>
         </Tab>
-        <Tab {...props.tab()} label="Tab label 2">
+        <Tab id="tab-2" {...props.tab()} label="Tab label 2">
           <div className="some-content">Content for second tab goes here.</div>
         </Tab>
         <Tab
+          id="tab-3"
           {...props.tab()}
           label="Tab label 3"
           renderContent={TabContentRenderedOnlyWhenSelected}>
           <div className="some-content">Content for third tab goes here.</div>
         </Tab>
-        <Tab {...props.tab()} label={<CustomLabel text="Custom Label" />}>
+        <Tab
+          id="tab-4"
+          {...props.tab()}
+          label={<CustomLabel text="Custom Label" />}>
           <div className="some-content">Content for fourth tab goes here.</div>
         </Tab>
       </Tabs>
diff --git a/packages/react/src/components/Tabs/Tabs.js b/packages/react/src/components/Tabs/Tabs.js
index 0fa5845e9dd3..99d1325de9dd 100644
--- a/packages/react/src/components/Tabs/Tabs.js
+++ b/packages/react/src/components/Tabs/Tabs.js
@@ -252,14 +252,21 @@ export default class Tabs extends React.Component {
     });
 
     const tabContentWithProps = React.Children.map(tabsWithProps, tab => {
-      const { children, selected, renderContent: TabContent } = tab.props;
+      const {
+        id: tabId,
+        children,
+        selected,
+        renderContent: TabContent,
+      } = tab.props;
 
       return (
         <TabContent
+          id={tabId && `${tabId}__panel`}
           className={tabContentClassName}
           aria-hidden={!selected}
           hidden={!selected}
-          selected={selected}>
+          selected={selected}
+          aria-labelledby={tabId}>
           {children}
         </TabContent>
       );