[react-interactions] Refactor TabFocusController (#16768)

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

@@ -0,0 +1,188 @@
+/**
+ * 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 type {ReactScopeMethods} from 'shared/ReactTypes';
+
+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,
+|};
+
+const {useRef} = React;
+
+function getTabbableNodes(scope: ReactScopeMethods) {
+  const tabbableNodes = scope.getScopedNodes();
+  if (tabbableNodes === null || tabbableNodes.length === 0) {
+    return [null, null, null, 0, null];
+  }
+  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 function focusFirst(scope: ReactScopeMethods): void {
+  const [, firstTabbableElem] = getTabbableNodes(scope);
+  focusElem(firstTabbableElem);
+}
+
+function focusElem(elem: null | HTMLElement): void {
+  if (elem !== null) {
+    elem.focus();
+  }
+}
+
+export function focusNext(
+  scope: ReactScopeMethods,
+  contain?: boolean,
+): boolean {
+  const [
+    tabbableNodes,
+    firstTabbableElem,
+    lastTabbableElem,
+    currentIndex,
+    focusedElement,
+  ] = getTabbableNodes(scope);
+
+  if (focusedElement === null) {
+    focusElem(firstTabbableElem);
+  } else if (focusedElement === lastTabbableElem) {
+    if (contain === true) {
+      focusElem(firstTabbableElem);
+    } else {
+      return true;
+    }
+  } else {
+    focusElem((tabbableNodes: any)[currentIndex + 1]);
+  }
+  return false;
+}
+
+export function focusPrevious(
+  scope: ReactScopeMethods,
+  contain?: boolean,
+): boolean {
+  const [
+    tabbableNodes,
+    firstTabbableElem,
+    lastTabbableElem,
+    currentIndex,
+    focusedElement,
+  ] = getTabbableNodes(scope);
+
+  if (focusedElement === null) {
+    focusElem(firstTabbableElem);
+  } else if (focusedElement === firstTabbableElem) {
+    if (contain === true) {
+      focusElem(lastTabbableElem);
+    } else {
+      return true;
+    }
+  } else {
+    focusElem((tabbableNodes: any)[currentIndex - 1]);
+  }
+  return false;
+}
+
+export function getNextController(
+  scope: ReactScopeMethods,
+): null | ReactScopeMethods {
+  const allScopes = scope.getChildrenFromRoot();
+  if (allScopes === null) {
+    return null;
+  }
+  const currentScopeIndex = allScopes.indexOf(scope);
+  if (currentScopeIndex === -1 || currentScopeIndex === allScopes.length - 1) {
+    return null;
+  }
+  return allScopes[currentScopeIndex + 1];
+}
+
+export function getPreviousController(
+  scope: ReactScopeMethods,
+): null | ReactScopeMethods {
+  const allScopes = scope.getChildrenFromRoot();
+  if (allScopes === null) {
+    return null;
+  }
+  const currentScopeIndex = allScopes.indexOf(scope);
+  if (currentScopeIndex <= 0) {
+    return null;
+  }
+  return allScopes[currentScopeIndex - 1];
+}
+
+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;
+        }
+        const scope = scopeRef.current;
+        if (scope !== null) {
+          if (event.shiftKey) {
+            return focusPrevious(scope, contain);
+          } else {
+            return focusNext(scope, contain);
+          }
+        }
+        return true;
+      },
+      preventKeys: ['Tab', ['Tab', {shiftKey: true}]],
+    });
+
+    return (
+      <TabbableScope
+        ref={node => {
+          if (ref) {
+            if (typeof ref === 'function') {
+              ref(node);
+            } else {
+              ref.current = node;
+            }
+          }
+          scopeRef.current = node;
+        }}
+        listeners={keyboard}>
+        {children}
+      </TabbableScope>
+    );
+  },
+);