wip: allow custom react element for S2 Picker value

packages/@react-spectrum/s2/src/Picker.tsx

@@ -123,7 +123,13 @@ export interface PickerProps<T extends object, M extends SelectionMode = 'single
     /** Width of the menu. By default, matches width of the trigger. Note that the minimum width of the dropdown is always equal to the trigger's width. */
     menuWidth?: number,
     /** The current loading state of the Picker. */
-    loadingState?: LoadingState
+    loadingState?: LoadingState,
+    /**
+     * Custom renderer for the picker value. Allows one to provide a custom element to render selected items.
+     *
+     * @note The returned ReactNode should not have interactable elements as it will break accessibility.
+     */
+    renderValue?: (selectedItems: T[]) => ReactNode
 }
 
 interface PickerButtonProps extends PickerStyleProps, ButtonRenderProps {}
@@ -227,7 +233,8 @@ const valueStyles = style({
   },
   truncate: true,
   display: 'flex',
-  alignItems: 'center'
+  alignItems: 'center',
+  height: '100%'
 });
 
 const iconStyles = style({
@@ -298,6 +305,7 @@ export const Picker = /*#__PURE__*/ (forwardRef as forwardRefType)(function Pick
     placeholder = stringFormatter.format('picker.placeholder'),
     isQuiet,
     loadingState,
+    renderValue,
     onLoadMore,
     ...pickerProps
   } = props;
@@ -377,6 +385,7 @@ export const Picker = /*#__PURE__*/ (forwardRef as forwardRefType)(function Pick
             </FieldLabel>
             <PickerButton
               loadingState={loadingState}
+              renderValue={renderValue}
               isOpen={isOpen}
               isQuiet={isQuiet}
               isFocusVisible={isFocusVisible}
@@ -483,7 +492,7 @@ const avatarSize = {
   XL: 26
 } as const;
 
-interface PickerButtonInnerProps<T extends object> extends PickerStyleProps, Omit<AriaSelectRenderProps, 'isRequired' | 'isFocused'>, Pick<PickerProps<T>, 'loadingState'> {
+interface PickerButtonInnerProps<T extends object> extends PickerStyleProps, Omit<AriaSelectRenderProps, 'isRequired' | 'isFocused'>, Pick<PickerProps<T>, 'loadingState' | 'renderValue'> {
   loadingCircle: ReactNode,
   buttonRef: RefObject<HTMLButtonElement | null>
 }
@@ -499,7 +508,8 @@ const PickerButton = createHideableComponent(function PickerButton<T extends obj
     isDisabled,
     loadingState,
     loadingCircle,
-    buttonRef
+    buttonRef,
+    renderValue
   } = props;
   let stringFormatter = useLocalizedStringFormatter(intlMessages, '@react-spectrum/s2');
 
@@ -531,8 +541,20 @@ const PickerButton = createHideableComponent(function PickerButton<T extends obj
         })}>
         {(renderProps) => (
           <>
-            <SelectValue className={valueStyles({isQuiet}) + ' ' + raw('&> :not([slot=icon], [slot=avatar], [slot=label], [data-slot=label]) {display: none;}')}>
+            <SelectValue
+              className={
+                valueStyles({isQuiet}) +
+                (renderValue ? '' : ' ' + raw('&> :not([slot=icon], [slot=avatar], [slot=label], [data-slot=label]) {display: none;}'))
+              }>
               {({selectedItems, defaultChildren}) => {
+                const selectedValues = selectedItems.filter((item): item is T => item != null);
+                const defaultRenderedValue = selectedItems.length <= 1
+                  ? defaultChildren
+                  : <Text slot="label">{stringFormatter.format('picker.selectedCount', {count: selectedItems.length})}</Text>;
+                const renderedValue = selectedItems.length > 0 && renderValue
+                  ? renderValue(selectedValues)
+                  : defaultRenderedValue;
+
                 return (
                   <Provider
                     values={[
@@ -577,10 +599,7 @@ const PickerButton = createHideableComponent(function PickerButton<T extends obj
                       }],
                       [InsideSelectValueContext, true]
                     ]}>
-                    {selectedItems.length <= 1
-                      ? defaultChildren
-                      : <Text slot="label">{stringFormatter.format('picker.selectedCount', {count: selectedItems.length})}</Text>
-                    }
+                    {renderedValue}
                   </Provider>
                 );
               }}

packages/@react-spectrum/s2/stories/Picker.stories.tsx

@@ -331,3 +331,39 @@ return (
     }
   }
 };
+
+
+type ExampleIconItem = IExampleItem & { icon: string };
+const exampleIconItems: ExampleIconItem[] = Array.from({length: 5}, (_, i) => ({
+  id: `user${i + 1}`,
+  label: `User ${i + 1}`,
+  icon: 'https://mir-s3-cdn-cf.behance.net/project_modules/disp/690bc6105945313.5f84bfc9de488.png',
+}));
+
+const CustomRenderValuePicker = (args: PickerProps<ExampleIconItem, 'multiple'>): ReactElement => (
+  <Picker {...args}>
+    {(item: ExampleIconItem) => (
+      <PickerItem id={item.id} textValue={item.label}>
+        <Avatar slot="avatar" src={item.icon} />
+        <Text slot="label">{item.label}</Text>
+      </PickerItem>
+    )}
+  </Picker>
+);
+
+export type CustomRenderValuePickerStoryType = typeof CustomRenderValuePicker;
+export const CustomRenderValue: StoryObj<CustomRenderValuePickerStoryType> = {
+  render: CustomRenderValuePicker,
+  args: {
+    label: 'Pick users',
+    selectionMode: 'multiple',
+    items: exampleIconItems,
+    renderValue: (selectedItems) => (
+      <div style={{display: 'flex', gap: 4, height: '80%'}}>
+        {selectedItems.map(item => (
+          <img key={item.id} src={item.icon} alt={item.label} />
+        ))}
+      </div>
+    )
+  }
+};

packages/@react-spectrum/s2/test/Picker.test.tsx

@@ -129,6 +129,42 @@ describe('Picker', () => {
     }
   });
 
+  it('should support custom renderValue output', async () => {
+    let items = [
+      {id: 'chocolate', name: 'Chocolate'},
+      {id: 'strawberry', name: 'Strawberry'},
+      {id: 'vanilla', name: 'Vanilla'}
+    ];
+    let renderValue = jest.fn((selectedItems) => (
+      <span data-testid="custom-value">
+        {selectedItems.map((item) => item.name).join(', ')}
+      </span>
+    ));
+    let tree = render(
+      <Picker
+        label="Test picker"
+        selectionMode="multiple"
+        items={items}
+        renderValue={renderValue}>
+        {(item: any) => <PickerItem id={item.id} textValue={item.name}>{item.name}</PickerItem>}
+      </Picker>
+    );
+
+    // expect the placeholder to be rendered when no items are selected
+    expect(tree.queryByTestId('custom-value')).toBeNull();
+
+    let selectTester = testUtilUser.createTester('Select', {root: tree.container, interactionType: 'mouse'});
+    await selectTester.open();
+    await selectTester.selectOption({option: 0});
+    await selectTester.selectOption({option: 2});
+    await selectTester.close();
+
+    // check that the clicked items are rendered in the custom renderValue output
+    let lastSelectedItems = renderValue.mock.calls[renderValue.mock.calls.length - 1][0];
+    expect(lastSelectedItems.map((item) => item.name)).toEqual(['Chocolate', 'Vanilla']);
+    expect(tree.getByTestId('custom-value')).toHaveTextContent('Chocolate, Vanilla');
+  });
+
   it('should support contextual help', async () => {
     // Issue with how we don't render the contextual help button in the fake DOM since PressResponder isn't using createHideableComponent
     let warn = jest.spyOn(global.console, 'warn').mockImplementation();

packages/dev/s2-docs/pages/s2/Picker.mdx

@@ -242,6 +242,54 @@ function Example(props) {
 }
 ```
 
+### Custom Render Value
+
+Use the `renderValue` prop to provide a custom element to display selected items. The callback is given an array of the selected user-defined objects.
+
+```tsx render
+"use client";
+import {Avatar, Picker, PickerItem, Text} from '@react-spectrum/s2';
+import {style} from '@react-spectrum/s2/style' with {type: 'macro'};
+import {useState} from 'react';
+
+function Example(props) {
+  const users = Array.from({length: 5}, (_, i) => ({
+    id: `user${i + 1}`,
+    name: `User ${i + 1}`,
+    email: `user${i + 1}@example.com`,
+    avatar: 'https://mir-s3-cdn-cf.behance.net/project_modules/disp/690bc6105945313.5f84bfc9de488.png',
+  }));
+
+  return (
+    <div>
+      <Picker
+        {...props}
+        label="Pick an animal"
+        items={users}
+        selectionMode={"multiple"}
+        ///- begin highlight -///
+        renderValue={(selectedItems) => (
+          <div style={{display: 'flex', gap: 4, height: '80%'}}>
+            {selectedItems.map(item => (
+              <img key={item.id} src={item.avatar} />
+            ))}
+          </div>
+        )}
+        ///- end highlight -///
+      >
+        {(item) =>
+          <PickerItem>
+            <Avatar slot="avatar" src={item.avatar} />
+            <Text slot="label">{item.name}</Text>
+            <Text slot="description">{item.email}</Text>
+          </PickerItem>
+        }
+      </Picker>
+    </div>
+  );
+}
+```
+
 ## Forms
 
 Use the `name` prop to submit the `id` of the selected item to the server. Set the `isRequired` prop to validate that the user selects an option, or implement custom client or server-side validation. See the [Forms](forms) guide to learn more.