fix(Tabs): ignore disabled tabs on keyboard navigation (#4784)

packages/react/src/components/Tab/Tab-test.js

@@ -101,21 +101,18 @@ describe('Tab', () => {
 
     describe('keydown', () => {
       const onKeyDown = jest.fn();
-      const handleTabAnchorFocus = jest.fn();
       const handleTabKeyDown = jest.fn();
       const wrapper = shallow(<Tab label="firstTab" />);
-      wrapper.setProps({ onKeyDown, handleTabAnchorFocus, handleTabKeyDown });
+      wrapper.setProps({ onKeyDown, handleTabKeyDown });
 
       it('invokes onKeyDown when a function is passed to onKeyDown prop', () => {
         wrapper.simulate('keyDown', { which: 38 });
         expect(onKeyDown).toBeCalled();
-        expect(handleTabAnchorFocus).not.toBeCalled();
       });
 
       it('invokes handleTabAnchorFocus when onKeyDown occurs for appropriate events', () => {
         wrapper.simulate('keyDown', { which: 37 });
         expect(onKeyDown).toBeCalled();
-        expect(handleTabAnchorFocus).toBeCalled();
       });
     });
   });

packages/react/src/components/Tab/Tab.js

@@ -26,12 +26,6 @@ export default class Tab extends React.Component {
      */
     handleTabClick: PropTypes.func,
 
-    /**
-     * A handler that is invoked when a user presses left/right key.
-     * Reserved for usage in Tabs
-     */
-    handleTabAnchorFocus: PropTypes.func,
-
     /**
      * A handler that is invoked on the key down event for the control.
      * Reserved for usage in Tabs
@@ -108,23 +102,10 @@ export default class Tab extends React.Component {
     onKeyDown: () => {},
   };
 
-  setTabFocus(evt) {
-    const leftKey = 37;
-    const rightKey = 39;
-    if (evt.which === leftKey) {
-      this.props.handleTabAnchorFocus(this.props.index - 1);
-    } else if (evt.which === rightKey) {
-      this.props.handleTabAnchorFocus(this.props.index + 1);
-    } else {
-      return;
-    }
-  }
-
   render() {
     const {
       className,
       handleTabClick,
-      handleTabAnchorFocus, // eslint-disable-line
       handleTabKeyDown,
       disabled,
       href,
@@ -172,7 +153,6 @@ export default class Tab extends React.Component {
           if (disabled) {
             return;
           }
-          this.setTabFocus(evt);
           handleTabKeyDown(index, evt);
           onKeyDown(evt);
         }}

packages/react/src/components/Tabs/Tabs-story.js

@@ -78,14 +78,17 @@ storiesOf('Tabs', module)
         <Tab {...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>
+          <div className="some-content">Content for third tab goes here.</div>
+        </Tab>
         <Tab
           {...props.tab()}
-          label="Tab label 3"
+          label="Tab label 4"
           renderContent={TabContentRenderedOnlyWhenSelected}>
-          <div className="some-content">Content for third tab goes here.</div>
+          <div className="some-content">Content for fourth tab goes here.</div>
         </Tab>
         <Tab {...props.tab()} label={<CustomLabel text="Custom Label" />}>
-          <div className="some-content">Content for fourth tab goes here.</div>
+          <div className="some-content">Content for fifth tab goes here.</div>
         </Tab>
       </Tabs>
     ),

packages/react/src/components/Tabs/Tabs-test.js

@@ -7,14 +7,25 @@
 
 import React from 'react';
 import { ChevronDownGlyph } from '@carbon/icons-react';
+import { settings } from 'carbon-components';
+import { shallow, mount } from 'enzyme';
 import Tabs from '../Tabs';
 import Tab from '../Tab';
 import TabsSkeleton from '../Tabs/Tabs.Skeleton';
-import { shallow, mount } from 'enzyme';
-import { settings } from 'carbon-components';
 
 const { prefix } = settings;
 
+window.matchMedia = jest.fn().mockImplementation(query => ({
+  matches: true,
+  media: query,
+  onchange: null,
+  addListener: jest.fn(), // deprecated
+  removeListener: jest.fn(), // deprecated
+  addEventListener: jest.fn(),
+  removeEventListener: jest.fn(),
+  dispatchEvent: jest.fn(),
+}));
+
 describe('Tabs', () => {
   describe('renders as expected', () => {
     describe('navigation (<div>)', () => {
@@ -241,6 +252,53 @@ describe('Tabs', () => {
           expect(wrapper.state().selected).toEqual(1);
         });
       });
+
+      describe('ignore disabled child tab', () => {
+        let wrapper;
+        let firstTab;
+        let lastTab;
+        beforeEach(() => {
+          wrapper = mount(
+            <Tabs>
+              <Tab label="firstTab" className="firstTab">
+                content1
+              </Tab>
+              <Tab label="middleTab" className="middleTab" disabled>
+                content2
+              </Tab>
+              <Tab label="lastTab" className="lastTab">
+                content3
+              </Tab>
+            </Tabs>
+          );
+          firstTab = wrapper.find('.firstTab').last();
+          lastTab = wrapper.find('.lastTab').last();
+        });
+        it('updates selected state when pressing arrow keys', () => {
+          firstTab.simulate('keydown', { which: rightKey });
+          expect(wrapper.state().selected).toEqual(2);
+          lastTab.simulate('keydown', { which: leftKey });
+          expect(wrapper.state().selected).toEqual(0);
+        });
+
+        it('loops focus and selected state from lastTab to firstTab', () => {
+          wrapper.setState({ selected: 2 });
+          lastTab.simulate('keydown', { which: rightKey });
+          expect(wrapper.state().selected).toEqual(0);
+        });
+
+        it('loops focus and selected state from firstTab to lastTab', () => {
+          firstTab.simulate('keydown', { which: leftKey });
+          expect(wrapper.state().selected).toEqual(2);
+        });
+
+        it('updates selected state when pressing space or enter key', () => {
+          firstTab.simulate('keydown', { which: spaceKey });
+          expect(wrapper.state().selected).toEqual(0);
+          lastTab.simulate('keydown', { which: enterKey });
+          expect(wrapper.state().selected).toEqual(2);
+        });
+      });
     });
   });
 

packages/react/src/components/Tabs/Tabs.js

@@ -10,6 +10,7 @@ import React from 'react';
 import classNames from 'classnames';
 import { ChevronDownGlyph } from '@carbon/icons-react';
 import { settings } from 'carbon-components';
+import { keys, match, matches } from '../../internal/keyboard';
 
 const { prefix } = settings;
 
@@ -116,6 +117,12 @@ export default class Tabs extends React.Component {
     return React.Children.map(this.props.children, tab => tab);
   }
 
+  getEnabledTabs = () =>
+    React.Children.toArray(this.props.children).reduce(
+      (acc, tab, index) => (!tab.props.disabled ? acc.concat(index) : acc),
+      []
+    );
+
   getTabAt = (index, useFresh) => {
     return (
       (!useFresh && this[`tab${index}`]) ||
@@ -139,35 +146,47 @@ export default class Tabs extends React.Component {
     };
   };
 
+  getDirection = evt => {
+    if (match(evt, keys.ArrowLeft)) {
+      return -1;
+    }
+    if (match(evt, keys.ArrowRight)) {
+      return 1;
+    }
+    return 0;
+  };
+
+  getNextIndex = (index, direction) => {
+    const enabledTabs = this.getEnabledTabs();
+    const nextIndex = Math.max(
+      enabledTabs.indexOf(index) + direction,
+      -1 /* For `tab` not found in `enabledTabs` */
+    );
+    const nextIndexLooped =
+      nextIndex >= 0 && nextIndex < enabledTabs.length
+        ? nextIndex
+        : nextIndex - Math.sign(nextIndex) * enabledTabs.length;
+    return enabledTabs[nextIndexLooped];
+  };
+
   handleTabKeyDown = onSelectionChange => {
     return (index, evt) => {
-      const key = evt.key || evt.which;
-
-      if (key === 'Enter' || key === 13 || key === ' ' || key === 32) {
+      if (matches(evt, [keys.Enter, keys.Space])) {
         this.selectTabAt(index, onSelectionChange);
         this.setState({
           dropdownHidden: true,
         });
       }
-    };
-  };
-
-  handleTabAnchorFocus = onSelectionChange => {
-    return index => {
-      const tabCount = React.Children.count(this.props.children) - 1;
-      let tabIndex = index;
-      if (index < 0) {
-        tabIndex = tabCount;
-      } else if (index > tabCount) {
-        tabIndex = 0;
-      }
-
-      const tab = this.getTabAt(tabIndex);
 
-      if (tab) {
-        this.selectTabAt(tabIndex, onSelectionChange);
-        if (tab.tabAnchor) {
-          tab.tabAnchor.focus();
+      if (window.matchMedia('(min-width: 42rem)').matches) {
+        evt.preventDefault();
+        const nextIndex = this.getNextIndex(index, this.getDirection(evt));
+        const tab = this.getTabAt(nextIndex);
+        if (tab) {
+          this.selectTabAt(nextIndex, onSelectionChange);
+          if (tab.tabAnchor) {
+            tab.tabAnchor.focus();
+          }
         }
       }
     };
@@ -222,7 +241,6 @@ export default class Tabs extends React.Component {
         index,
         selected: index === this.state.selected,
         handleTabClick: this.handleTabClick(onSelectionChange),
-        handleTabAnchorFocus: this.handleTabAnchorFocus(onSelectionChange),
         tabIndex,
         ref: e => {
           this.setTabAt(index, e);