Update `SidebarPanel` to use `Panel` component

src/sidebar/components/SidebarPanel.js

-import { SvgIcon } from '@hypothesis/frontend-shared';
-import { useEffect, useRef } from 'preact/hooks';
+import { useCallback, useEffect, useRef } from 'preact/hooks';
 import scrollIntoView from 'scroll-into-view';
 
 import { useStoreProxy } from '../store/use-store';
 
-import Button from './Button';
+import Panel from './Panel';
 import Slider from './Slider';
 
 /**
@@ -13,22 +12,19 @@ import Slider from './Slider';
 
 /**
  * @typedef SidebarPanelProps
- * @prop {Object} [children]
+ * @prop {import("preact").ComponentChildren} children
  * @prop {string} [icon] - An optional icon name for display next to the panel's title
  * @prop {PanelName} panelName -
  *   A string identifying this panel. Only one `panelName` may be active at any time.
  *   Multiple panels with the same `panelName` would be "in sync", opening and closing together.
- * @prop {string} title - The panel's title: rendered in its containing visual "frame"
+ * @prop {string} title - The panel's title
  * @prop {(active: boolean) => any} [onActiveChanged] -
  *   Optional callback to invoke when this panel's active status changes
  */
 
 /**
- * Base component for a sidebar panel.
- *
- * This component provides a basic visual container for sidebar panels, as well
- * as providing a close button. Only one sidebar panel (as defined by the panel's
- * `panelName`) is active at one time.
+ * Base component for a sidebar panel. Only one sidebar panel
+ * (as defined by the panel's `panelName`) is active (visible) at one time.
  *
  * @param {SidebarPanelProps} props
  */
@@ -58,25 +54,16 @@ export default function SidebarPanel({
     }
   }, [panelIsActive, onActiveChanged]);
 
-  const closePanel = () => {
+  const closePanel = useCallback(() => {
     store.toggleSidebarPanel(panelName, false);
-  };
+  }, [store, panelName]);
 
   return (
     <Slider visible={panelIsActive}>
-      <div className="SidebarPanel" ref={panelElement}>
-        <div className="SidebarPanel__header">
-          {icon && (
-            <div className="SidebarPanel__header-icon">
-              <SvgIcon name={icon} title={title} />
-            </div>
-          )}
-          <h2 className="SidebarPanel__title u-stretch">{title}</h2>
-          <div>
-            <Button icon="cancel" buttonText="Close" onClick={closePanel} />
-          </div>
-        </div>
-        <div className="SidebarPanel__content">{children}</div>
+      <div ref={panelElement}>
+        <Panel title={title} icon={icon} onClose={closePanel}>
+          {children}
+        </Panel>
       </div>
     </Slider>
   );

src/sidebar/components/test/SidebarPanel-test.js

@@ -37,24 +37,22 @@ describe('SidebarPanel', () => {
     $imports.$restore();
   });
 
-  it('renders the provided title', () => {
-    const wrapper = createSidebarPanel({ title: 'My Panel' });
-    const titleEl = wrapper.find('.SidebarPanel__title');
-    assert.equal(titleEl.text(), 'My Panel');
+  it('renders a panel with provided title and icon', () => {
+    const wrapper = createSidebarPanel({
+      title: 'My Panel',
+      icon: 'restricted',
     });
 
-  it('renders an icon if provided', () => {
-    const wrapper = createSidebarPanel({ icon: 'restricted' });
+    const panel = wrapper.find('Panel');
 
-    const icon = wrapper.find('SvgIcon').filter({ name: 'restricted' });
-
-    assert.isTrue(icon.exists());
+    assert.equal(panel.props().icon, 'restricted');
+    assert.equal(panel.props().title, 'My Panel');
   });
 
-  it('closes the panel when close button is clicked', () => {
+  it('provides an `onClose` handler that closes the panel', () => {
     const wrapper = createSidebarPanel({ panelName: 'flibberty' });
 
-    wrapper.find('Button').props().onClick();
+    wrapper.find('Panel').props().onClose();
 
     assert.calledWith(fakeStore.toggleSidebarPanel, 'flibberty', false);
   });

src/styles/sidebar/components/SidebarPanel.scss

-@use "../../mixins/molecules";
-
-.SidebarPanel {
-  @include molecules.panel;
-  position: relative;
-  margin-bottom: 0.75em;
-}

src/styles/sidebar/sidebar.scss

@@ -48,7 +48,6 @@
 @use './components/SearchInput';
 @use './components/ShareLinks';
 @use './components/SidebarContentError';
-@use './components/SidebarPanel';
 @use './components/Spinner';
 @use './components/TagEditor';
 @use './components/TagList';