[DevTools] Show list of named Activities in Suspense tab

packages/react-devtools-shared/src/devtools/store.js

@@ -1058,6 +1058,33 @@ export default class Store extends EventEmitter<{
     return timeline;
   }
 
+  getActivities(): Array<{id: Element['id'], depth: number}> {
+    const target: Array<{id: Element['id'], depth: number}> = [];
+    // TODO: Keep a live tree in the backend so we don't need to recalculate
+    // this each time while also including filtered Activities.
+    this._pushActivitiesInDocumentOrder(this.roots, target, 0);
+    return target;
+  }
+
+  _pushActivitiesInDocumentOrder(
+    children: $ReadOnlyArray<Element['id']>,
+    target: Array<{id: Element['id'], depth: number}>,
+    depth: number,
+  ): void {
+    for (let i = 0; i < children.length; i++) {
+      const child = this._idToElement.get(children[i]);
+      if (child === undefined) {
+        continue;
+      }
+      if (child.type === ElementTypeActivity && child.nameProp !== null) {
+        target.push({id: child.id, depth});
+        this._pushActivitiesInDocumentOrder(child.children, target, depth + 1);
+      } else {
+        this._pushActivitiesInDocumentOrder(child.children, target, depth);
+      }
+    }
+  }
+
   getRendererIDForElement(id: number): number | null {
     let current = this._idToElement.get(id);
     while (current !== undefined) {

packages/react-devtools-shared/src/devtools/views/Components/TreeContext.js

@@ -59,6 +59,7 @@ export type StateContext = {
 
   // Activity slice
   activityID: Element['id'] | null,
+  activities: $ReadOnlyArray<{id: Element['id'], depth: number}>,
 
   // Inspection element panel
   inspectedElementID: number | null,
@@ -172,6 +173,7 @@ type State = {
 
   // Activity slice
   activityID: Element['id'] | null,
+  activities: $ReadOnlyArray<{id: Element['id'], depth: number}>,
 
   // Inspection element panel
   inspectedElementID: number | null,
@@ -809,6 +811,7 @@ function reduceActivityState(
     case 'HANDLE_STORE_MUTATION':
       let {activityID} = state;
       const [, , activitySliceIDChange] = action.payload;
+      const activities = store.getActivities();
       if (activitySliceIDChange === 0 && activityID !== null) {
         activityID = null;
       } else if (
@@ -817,10 +820,11 @@ function reduceActivityState(
       ) {
         activityID = activitySliceIDChange;
       }
-      if (activityID !== state.activityID) {
+      if (activityID !== state.activityID || activities !== state.activities) {
         return {
           ...state,
           activityID,
+          activities,
         };
       }
   }
@@ -863,6 +867,7 @@ function getInitialState({
 
     // Activity slice
     activityID: null,
+    activities: store.getActivities(),
 
     // Inspection element panel
     inspectedElementID:

packages/react-devtools-shared/src/devtools/views/SuspenseTab/ActivityList.css

@@ -1,20 +1,33 @@
-.ActivityList {
+.ActivityListContaier {
+  display: flex;
+  flex-direction: column;
+}
+
+.ActivityListHeader {
+  /* even if empty, provides layout alignment with the main view */
+  display: flex;
+  flex: 0 0 42px;
+  border-bottom: 1px solid var(--color-border);
+}
+
+.ActivityListList {
   cursor: default;
   list-style-type: none;
   margin: 0;
   padding: 0;
 }
 
-.ActivityList[data-pending-activity-slice-selection="true"] {
+.ActivityListList[data-pending-activity-slice-selection="true"] {
   cursor: wait;
 }
 
-.ActivityList:focus {
+.ActivityListList:focus {
   outline: none;
 }
 
 .ActivityListItem {
   color: var(--color-component-name);
+  line-height: var(--line-height-data);
   padding: 0 0.25rem;
   user-select: none;
 }
@@ -27,7 +40,7 @@
   background-color: var(--color-background-inactive);
 }
 
-.ActivityList:focus .ActivityListItem[aria-selected="true"] {
+.ActivityListList:focus .ActivityListItem[aria-selected="true"] {
   background-color: var(--color-background-selected);
   color: var(--color-text-selected);
 

packages/react-devtools-shared/src/devtools/views/SuspenseTab/ActivityList.js

@@ -15,17 +15,23 @@ import typeof {
   SyntheticMouseEvent,
   SyntheticKeyboardEvent,
 } from 'react-dom-bindings/src/events/SyntheticEvent';
+import type Store from 'react-devtools-shared/src/devtools/store';
 
 import * as React from 'react';
-import {useContext, useTransition} from 'react';
-import {ComponentFilterActivitySlice} from 'react-devtools-shared/src/frontend/types';
+import {useContext, useMemo, useTransition} from 'react';
+import {
+  ComponentFilterActivitySlice,
+  ElementTypeActivity,
+} from 'react-devtools-shared/src/frontend/types';
 import styles from './ActivityList.css';
 import {
   TreeStateContext,
   TreeDispatcherContext,
 } from '../Components/TreeContext';
 import {useHighlightHostInstance} from '../hooks';
 import {StoreContext} from '../context';
+import ButtonIcon from '../ButtonIcon';
+import Button from '../Button';
 
 export function useChangeActivitySliceAction(): (
   id: Element['id'] | null,
@@ -62,15 +68,49 @@ export function useChangeActivitySliceAction(): (
   return changeActivitySliceAction;
 }
 
+function findNearestActivityParentID(
+  elementID: Element['id'],
+  store: Store,
+): Element['id'] | null {
+  let currentID: null | Element['id'] = elementID;
+  while (currentID !== null) {
+    const element = store.getElementByID(currentID);
+    if (element === null) {
+      return null;
+    }
+    if (element.type === ElementTypeActivity) {
+      return element.id;
+    }
+    currentID = element.parentID;
+  }
+
+  return currentID;
+}
+
+function useSelectedActivityID(): Element['id'] | null {
+  const {inspectedElementID} = useContext(TreeStateContext);
+  const store = useContext(StoreContext);
+  return useMemo(() => {
+    if (inspectedElementID === null) {
+      return null;
+    }
+    const nearestActivityID = findNearestActivityParentID(
+      inspectedElementID,
+      store,
+    );
+    return nearestActivityID;
+  }, [inspectedElementID, store]);
+}
+
 export default function ActivityList({
   activities,
 }: {
-  activities: $ReadOnlyArray<Element>,
+  activities: $ReadOnlyArray<{id: Element['id'], depth: number}>,
 }): React$Node {
-  const {inspectedElementID} = useContext(TreeStateContext);
+  const {activityID, inspectedElementID} = useContext(TreeStateContext);
   const treeDispatch = useContext(TreeDispatcherContext);
-  // TODO: Derive from inspected element
-  const selectedActivityID = inspectedElementID;
+  const store = useContext(StoreContext);
+  const selectedActivityID = useSelectedActivityID();
   const {highlightHostInstance, clearHighlightHostInstance} =
     useHighlightHostInstance();
 
@@ -79,8 +119,13 @@ export default function ActivityList({
   const changeActivitySliceAction = useChangeActivitySliceAction();
 
   function handleKeyDown(event: SyntheticKeyboardEvent) {
-    // TODO: Implement keyboard navigation
     switch (event.key) {
+      case 'Escape':
+        startActivitySliceSelection(() => {
+          changeActivitySliceAction(null);
+        });
+        event.preventDefault();
+        break;
       case 'Enter':
       case ' ':
         if (inspectedElementID !== null) {
@@ -149,25 +194,61 @@ export default function ActivityList({
   }
 
   return (
-    <ol
-      role="listbox"
-      className={styles.ActivityList}
-      data-pending-activity-slice-selection={isPendingActivitySliceSelection}
-      tabIndex={0}
-      onKeyDown={handleKeyDown}>
-      {activities.map(activity => (
-        <li
-          key={activity.id}
-          role="option"
-          aria-selected={activity.id === selectedActivityID ? 'true' : 'false'}
-          className={styles.ActivityListItem}
-          onClick={handleClick.bind(null, activity.id)}
-          onDoubleClick={handleDoubleClick}
-          onPointerOver={highlightHostInstance.bind(null, activity.id, false)}
-          onPointerLeave={clearHighlightHostInstance}>
-          {activity.nameProp}
-        </li>
-      ))}
-    </ol>
+    <div className={styles.ActivityListContaier}>
+      <div className={styles.ActivityListHeader}>
+        {activityID !== null && (
+          // TODO: Obsolete once filtered Activities are included in this list.
+          <Button
+            onClick={startActivitySliceSelection.bind(
+              null,
+              changeActivitySliceAction.bind(null, null),
+            )}
+            title="Back to full tree view">
+            <ButtonIcon type="previous" />
+          </Button>
+        )}
+      </div>
+      <ol
+        role="listbox"
+        className={styles.ActivityListList}
+        data-pending-activity-slice-selection={isPendingActivitySliceSelection}
+        tabIndex={0}
+        onKeyDown={handleKeyDown}>
+        {activities.map(({id, depth}) => {
+          const activity = store.getElementByID(id);
+          if (activity === null) {
+            return null;
+          }
+          const name = activity.nameProp;
+          if (name === null) {
+            // This shouldn't actually happen. We only want to show activities with a name.
+            // And hide the whole list if no named Activities are present.
+            return null;
+          }
+
+          // TODO: Filtered Activities should have dedicated styles once we include
+          // filtered Activities in this list.
+          return (
+            <li
+              key={activity.id}
+              role="option"
+              aria-selected={
+                activity.id === selectedActivityID ? 'true' : 'false'
+              }
+              className={styles.ActivityListItem}
+              onClick={handleClick.bind(null, activity.id)}
+              onDoubleClick={handleDoubleClick}
+              onPointerOver={highlightHostInstance.bind(
+                null,
+                activity.id,
+                false,
+              )}
+              onPointerLeave={clearHighlightHostInstance}>
+              {'\u00A0'.repeat(depth) + name}
+            </li>
+          );
+        })}
+      </ol>
+    </div>
   );
 }

packages/react-devtools-shared/src/devtools/views/SuspenseTab/SuspenseTab.css

@@ -92,7 +92,7 @@
 }
 
 .ActivityList {
-  flex: 0 0 var(--horizontal-resize-tree-list-percentage);
+  flex: 0 0 var(--horizontal-resize-activity-list-percentage);;
   border-right: 1px solid var(--color-border);
   overflow: auto;
 }