feat(treeview): add experimental controllable API

packages/feature-flags/feature-flags.yml

@@ -34,3 +34,7 @@ feature-flags:
     description: >
       Enable the use of the v12 OverflowMenu leveraging the Menu subcomponents
     enabled: false
+  - name: enable-treeview-controllable
+    description: >
+      Enable the new TreeView controllable API
+    enabled: false

packages/react/__tests__/__snapshots__/PublicAPI-test.js.snap

@@ -9175,6 +9175,9 @@ Map {
       "className": Object {
         "type": "string",
       },
+      "defaultIsExpanded": Object {
+        "type": "bool",
+      },
       "depth": Object {
         "type": "number",
       },
@@ -9262,6 +9265,9 @@ Map {
         "className": Object {
           "type": "string",
         },
+        "defaultIsExpanded": Object {
+          "type": "bool",
+        },
         "depth": Object {
           "type": "number",
         },
@@ -9356,6 +9362,9 @@ Map {
       "multiselect": Object {
         "type": "bool",
       },
+      "onActivate": Object {
+        "type": "func",
+      },
       "onSelect": Object {
         "type": "func",
       },

packages/react/src/components/FeatureFlags/overview.stories.mdx

@@ -34,8 +34,9 @@ components with all feature flags turned on.
 | ----------------------------------- | ------------------------------------------------------------------------ | ------- | --------------- | --------- |
 | `enable-v11-release`                | Flag enabling the v11 features                                           | `true`  | ✅              | ✅        |
 | `enable-experimental-tile-contrast` | Enable the improved styling for tiles that provides better contrast      | `false` |                 | ✅        |
-| `enable-v12-tile-default-icons`     | Enable default icons for Tile components                                 | `false` | ✅              |
-| `enable-v12-overflowmenu`           | Enable the use of the v12 OverflowMenu leveraging the Menu subcomponents | `false` | ✅              |
+| `enable-v12-tile-default-icons`     | Enable default icons for Tile components                                 | `false` | ✅              |           |
+| `enable-v12-overflowmenu`           | Enable the use of the v12 OverflowMenu leveraging the Menu subcomponents | `false` | ✅              |           |
+| `enable-treeview-controllable`      | Enable the new TreeView controllable API                                 | `false` | ✅              |           |
 
 ## Turning on feature flags in Javascript/react
 

packages/react/src/components/TreeView/TreeNode.js

@@ -12,6 +12,8 @@ import classNames from 'classnames';
 import { keys, match, matches } from '../../internal/keyboard';
 import uniqueId from '../../tools/uniqueId';
 import { usePrefix } from '../../internal/usePrefix';
+import { useControllableState } from '../../internal/useControllableState';
+import { useFeatureFlag } from '../FeatureFlags';
 
 const TreeNode = React.forwardRef(
   (
@@ -23,6 +25,7 @@ const TreeNode = React.forwardRef(
       disabled,
       id: nodeId,
       isExpanded,
+      defaultIsExpanded,
       label,
       onNodeFocusEvent,
       onSelect: onNodeSelect,
@@ -35,8 +38,22 @@ const TreeNode = React.forwardRef(
     },
     ref
   ) => {
+    const enableTreeviewControllable = useFeatureFlag(
+      'enable-treeview-controllable'
+    );
+
     const { current: id } = useRef(nodeId || uniqueId());
-    const [expanded, setExpanded] = useState(isExpanded);
+
+    const controllableExpandedState = useControllableState({
+      value: isExpanded,
+      onChange: onToggle,
+      defaultValue: defaultIsExpanded,
+    });
+    const uncontrollableExpandedState = useState(isExpanded);
+    const [expanded, setExpanded] = enableTreeviewControllable
+      ? controllableExpandedState
+      : uncontrollableExpandedState;
+
     const currentNode = useRef(null);
     const currentNodeLabel = useRef(null);
     const prefix = usePrefix();
@@ -76,7 +93,9 @@ const TreeNode = React.forwardRef(
       // Prevent the node from being selected
       event.stopPropagation();
 
-      onToggle?.(event, { id, isExpanded: !expanded, label, value });
+      if (!enableTreeviewControllable) {
+        onToggle?.(event, { id, isExpanded: !expanded, label, value });
+      }
       setExpanded(!expanded);
     }
     function handleClick(event) {
@@ -105,7 +124,9 @@ const TreeNode = React.forwardRef(
           return findParentTreeNode(node.parentNode);
         };
         if (children && expanded) {
-          onToggle?.(event, { id, isExpanded: false, label, value });
+          if (!enableTreeviewControllable) {
+            onToggle?.(event, { id, isExpanded: false, label, value });
+          }
           setExpanded(false);
         } else {
           /**
@@ -123,7 +144,9 @@ const TreeNode = React.forwardRef(
            */
           currentNode.current.lastChild.firstChild.focus();
         } else {
-          onToggle?.(event, { id, isExpanded: true, label, value });
+          if (!enableTreeviewControllable) {
+            onToggle?.(event, { id, isExpanded: true, label, value });
+          }
           setExpanded(true);
         }
       }
@@ -177,9 +200,18 @@ const TreeNode = React.forwardRef(
         currentNodeLabel.current.style.paddingInlineStart = `${calcOffset()}rem`;
       }
 
-      // sync props and state
-      setExpanded(isExpanded);
-    }, [children, depth, Icon, isExpanded]);
+      if (!enableTreeviewControllable) {
+        // sync props and state
+        setExpanded(isExpanded);
+      }
+    }, [
+      children,
+      depth,
+      Icon,
+      isExpanded,
+      enableTreeviewControllable,
+      setExpanded,
+    ]);
 
     const treeNodeProps = {
       ...rest,
@@ -251,7 +283,13 @@ TreeNode.propTypes = {
   className: PropTypes.string,
 
   /**
-   * * **Note:** this is controlled by the parent TreeView component, do not set manually.
+   * **[Experimental]** The default expansion state of the node.
+   * *This is only supported with the `enable-treeview-controllable` feature flag!*
+   */
+  defaultIsExpanded: PropTypes.bool,
+
+  /**
+   * **Note:** this is controlled by the parent TreeView component, do not set manually.
    * TreeNode depth to determine spacing
    */
   depth: PropTypes.number,

packages/react/src/components/TreeView/TreeView.featureflag.mdx

@@ -0,0 +1,33 @@
+# TreeView controllable API
+
+The new controllable API of TreeView allows you to synchronize the state of `selected` and `active` with your application.
+
+You can opt-in to this by enabling the `enable-treeview-controllable` feature flag. This changes the following behaviour:
+
+- `TreeView`
+  - `props.onActivate` will be called with a node's ID whenever it is activated.
+  - The signature of `props.onSelect` changes from `(event, selectedIDs)` to `(selectedIDs)`.
+  - Whenever you update `props.selected` or `props.active`, the internal state will be updated accordingly and the component re-renders.
+- `TreeNode`
+  - The signature of `props.onToggle` changes from `(event, { id, isExpanded, label, value })` to `(isExpanded)`.
+  - `props.defaultIsExpanded` is added to allow for a default state in uncontrolled mode.
+
+## Example
+
+```jsx
+function SynchronizedTreeView() {
+  const [selected, setSelected] = useState([]);
+  const [active, setActive] = useState(null);
+
+  return (
+    <TreeView
+      selected={selected}
+      onSelect={setSelected}
+      active={active}
+      onActivate={setActive}
+    >
+      ...
+    </TreeView>
+  );
+}
+```