[react-interactions] More Tab Focus control handling (#16751)

packages/react-dom/src/client/focus/TabFocusController.js

@@ -0,0 +1,179 @@
+/**
+ * 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.
+ *
+ * @flow
+ */
+
+import React from 'react';
+import {TabbableScope} from './TabbableScope';
+import {useKeyboard} from 'react-events/keyboard';
+
+type TabFocusControllerProps = {
+  children: React.Node,
+  contain?: boolean,
+};
+
+type KeyboardEventType = 'keydown' | 'keyup';
+
+type KeyboardEvent = {|
+  altKey: boolean,
+  ctrlKey: boolean,
+  isComposing: boolean,
+  key: string,
+  metaKey: boolean,
+  shiftKey: boolean,
+  target: Element | Document,
+  type: KeyboardEventType,
+  timeStamp: number,
+  defaultPrevented: boolean,
+|};
+
+type ControllerHandle = {|
+  focusFirst: () => void,
+  focusNext: () => boolean,
+  focusPrevious: () => boolean,
+  getNextController: () => null | ControllerHandle,
+  getPreviousController: () => null | ControllerHandle,
+|};
+
+const {useImperativeHandle, useRef} = React;
+
+function getTabbableNodes(scopeRef) {
+  const tabbableScope = scopeRef.current;
+  const tabbableNodes = tabbableScope.getScopedNodes();
+  const firstTabbableElem = tabbableNodes[0];
+  const lastTabbableElem = tabbableNodes[tabbableNodes.length - 1];
+  const currentIndex = tabbableNodes.indexOf(document.activeElement);
+  let focusedElement = null;
+  if (currentIndex !== -1) {
+    focusedElement = tabbableNodes[currentIndex];
+  }
+  return [
+    tabbableNodes,
+    firstTabbableElem,
+    lastTabbableElem,
+    currentIndex,
+    focusedElement,
+  ];
+}
+
+export const TabFocusController = React.forwardRef(
+  ({children, contain}: TabFocusControllerProps, ref): React.Node => {
+    const scopeRef = useRef(null);
+    const keyboard = useKeyboard({
+      onKeyDown(event: KeyboardEvent): boolean {
+        if (event.key !== 'Tab') {
+          return true;
+        }
+        if (event.shiftKey) {
+          return focusPrevious();
+        } else {
+          return focusNext();
+        }
+      },
+      preventKeys: ['Tab', ['Tab', {shiftKey: true}]],
+    });
+
+    function focusFirst(): void {
+      const [, firstTabbableElem] = getTabbableNodes(scopeRef);
+      firstTabbableElem.focus();
+    }
+
+    function focusNext(): boolean {
+      const [
+        tabbableNodes,
+        firstTabbableElem,
+        lastTabbableElem,
+        currentIndex,
+        focusedElement,
+      ] = getTabbableNodes(scopeRef);
+
+      if (focusedElement === null) {
+        firstTabbableElem.focus();
+      } else if (focusedElement === lastTabbableElem) {
+        if (contain === true) {
+          firstTabbableElem.focus();
+        } else {
+          return true;
+        }
+      } else {
+        tabbableNodes[currentIndex + 1].focus();
+      }
+      return false;
+    }
+
+    function focusPrevious(): boolean {
+      const [
+        tabbableNodes,
+        firstTabbableElem,
+        lastTabbableElem,
+        currentIndex,
+        focusedElement,
+      ] = getTabbableNodes(scopeRef);
+
+      if (focusedElement === null) {
+        firstTabbableElem.focus();
+      } else if (focusedElement === firstTabbableElem) {
+        if (contain === true) {
+          lastTabbableElem.focus();
+        } else {
+          return true;
+        }
+      } else {
+        tabbableNodes[currentIndex - 1].focus();
+      }
+      return false;
+    }
+
+    function getPreviousController(): null | ControllerHandle {
+      const tabbableScope = scopeRef.current;
+      const allScopes = tabbableScope.getChildrenFromRoot();
+      if (allScopes === null) {
+        return null;
+      }
+      const currentScopeIndex = allScopes.indexOf(tabbableScope);
+      if (currentScopeIndex <= 0) {
+        return null;
+      }
+      return allScopes[currentScopeIndex - 1].getHandle();
+    }
+
+    function getNextController(): null | ControllerHandle {
+      const tabbableScope = scopeRef.current;
+      const allScopes = tabbableScope.getChildrenFromRoot();
+      if (allScopes === null) {
+        return null;
+      }
+      const currentScopeIndex = allScopes.indexOf(tabbableScope);
+      if (
+        currentScopeIndex === -1 ||
+        currentScopeIndex === allScopes.length - 1
+      ) {
+        return null;
+      }
+      return allScopes[currentScopeIndex + 1].getHandle();
+    }
+
+    const controllerHandle: ControllerHandle = {
+      focusFirst,
+      focusNext,
+      focusPrevious,
+      getNextController,
+      getPreviousController,
+    };
+
+    useImperativeHandle(ref, () => controllerHandle);
+
+    return (
+      <TabbableScope
+        ref={scopeRef}
+        handle={controllerHandle}
+        listeners={keyboard}>
+        {children}
+      </TabbableScope>
+    );
+  },
+);