feat(UnderlineNavItem): add support for icons as React.ReactElement (#4718)

* feat(UnderlineNavItem): add support for icons as React.ReactElement

* chore: add changeset

* fix: update render logic for elements, update stories

* chore: update typescript for storybook

---------

Co-authored-by: Josh Black <joshblack@users.noreply.github.com>

Author: joshblack

.changeset/bright-islands-kick.md

@@ -0,0 +1,5 @@
+---
+'@primer/react': minor
+---
+
+Add support for providing icons as an element to UnderlineNavItem

packages/react/src/UnderlineNav/UnderlineNav.features.stories.tsx

@@ -16,9 +16,11 @@ import type {Meta} from '@storybook/react'
 import {UnderlineNav} from './index'
 import {INITIAL_VIEWPORTS} from '@storybook/addon-viewport'
 
-export default {
+const meta = {
   title: 'Components/UnderlineNav/Features',
-} as Meta
+} satisfies Meta<typeof UnderlineNav>
+
+export default meta
 
 export const Default = () => {
   return (
@@ -33,28 +35,28 @@ export const Default = () => {
 export const WithIcons = () => {
   return (
     <UnderlineNav aria-label="Repository with icons">
-      <UnderlineNav.Item icon={CodeIcon}>Code</UnderlineNav.Item>
-      <UnderlineNav.Item icon={EyeIcon} counter={6}>
+      <UnderlineNav.Item icon={<CodeIcon />}>Code</UnderlineNav.Item>
+      <UnderlineNav.Item icon={<EyeIcon />} counter={6}>
         Issues
       </UnderlineNav.Item>
-      <UnderlineNav.Item aria-current="page" icon={GitPullRequestIcon}>
+      <UnderlineNav.Item aria-current="page" icon={<GitPullRequestIcon />}>
         Pull Requests
       </UnderlineNav.Item>
-      <UnderlineNav.Item icon={CommentDiscussionIcon} counter={7}>
+      <UnderlineNav.Item icon={<CommentDiscussionIcon />} counter={7}>
         Discussions
       </UnderlineNav.Item>
-      <UnderlineNav.Item icon={ProjectIcon}>Projects</UnderlineNav.Item>
+      <UnderlineNav.Item icon={<ProjectIcon />}>Projects</UnderlineNav.Item>
     </UnderlineNav>
   )
 }
 
 export const WithCounterLabels = () => {
   return (
     <UnderlineNav aria-label="Repository with counters">
-      <UnderlineNav.Item aria-current="page" icon={CodeIcon} counter="11K">
+      <UnderlineNav.Item aria-current="page" icon={<CodeIcon />} counter="11K">
         Code
       </UnderlineNav.Item>
-      <UnderlineNav.Item icon={IssueOpenedIcon} counter={12}>
+      <UnderlineNav.Item icon={<IssueOpenedIcon />} counter={12}>
         Issues
       </UnderlineNav.Item>
     </UnderlineNav>

packages/react/src/UnderlineNav/UnderlineNav.stories.tsx

@@ -5,10 +5,9 @@ import {UnderlineNavItem} from './UnderlineNavItem'
 
 const excludedControlKeys = ['sx', 'as', 'variant', 'align', 'afterSelect']
 
-export default {
+const meta: Meta<typeof UnderlineNav> = {
   title: 'Components/UnderlineNav',
   component: UnderlineNav,
-  subcomponents: {UnderlineNavItem},
   parameters: {
     controls: {
       expanded: true,
@@ -33,7 +32,9 @@ export default {
     'aria-label': 'Repository',
     loadingCounters: false,
   },
-} as Meta<typeof UnderlineNav>
+}
+
+export default meta
 
 export const Default: StoryFn<typeof UnderlineNav> = () => {
   const children = ['Code', 'Pull requests', 'Actions', 'Projects', 'Wiki']

packages/react/src/UnderlineNav/UnderlineNav.test.tsx

@@ -1,5 +1,5 @@
 import React from 'react'
-import {render} from '@testing-library/react'
+import {render, screen} from '@testing-library/react'
 import userEvent from '@testing-library/user-event'
 import type {IconProps} from '@primer/octicons-react'
 import {
@@ -77,22 +77,26 @@ describe('UnderlineNav', () => {
     default: undefined,
     UnderlineNav,
   })
+
   it('renders aria-current attribute to be pages when an item is selected', () => {
     const {getByRole} = render(<ResponsiveUnderlineNav />)
     const selectedNavLink = getByRole('link', {name: 'Code'})
     expect(selectedNavLink.getAttribute('aria-current')).toBe('page')
   })
+
   it('renders aria-label attribute correctly', () => {
     const {container, getByRole} = render(<ResponsiveUnderlineNav />)
     expect(container.getElementsByTagName('nav').length).toEqual(1)
     const nav = getByRole('navigation')
     expect(nav.getAttribute('aria-label')).toBe('Repository')
   })
+
   it('renders icons correctly', () => {
     const {getByRole} = render(<ResponsiveUnderlineNav />)
     const nav = getByRole('navigation')
     expect(nav.getElementsByTagName('svg').length).toEqual(7)
   })
+
   it('fires onSelect on click', async () => {
     const onSelect = jest.fn()
     const {getByRole} = render(
@@ -107,6 +111,7 @@ describe('UnderlineNav', () => {
     await user.click(item)
     expect(onSelect).toHaveBeenCalledTimes(1)
   })
+
   it('fires onSelect on keypress', async () => {
     const onSelect = jest.fn()
     const {getByRole} = render(
@@ -128,27 +133,31 @@ describe('UnderlineNav', () => {
     await user.keyboard(' ') // space
     expect(onSelect).toHaveBeenCalledTimes(3)
   })
+
   it('respects counter prop', () => {
     const {getByRole} = render(<ResponsiveUnderlineNav />)
     const item = getByRole('link', {name: 'Issues (120)'})
     const counter = item.getElementsByTagName('span')[3]
     expect(counter.textContent).toBe('120')
     expect(counter).toHaveAttribute('aria-hidden', 'true')
   })
+
   it('renders the content of visually hidden span properly for screen readers', () => {
     const {getByRole} = render(<ResponsiveUnderlineNav />)
     const item = getByRole('link', {name: 'Issues (120)'})
     const counter = item.getElementsByTagName('span')[4]
     // non breaking space unified code
     expect(counter.textContent).toBe('\u00A0(120)')
   })
+
   it('respects loadingCounters prop', () => {
     const {getByRole} = render(<ResponsiveUnderlineNav loadingCounters={true} />)
     const item = getByRole('link', {name: 'Actions'})
     const loadingCounter = item.getElementsByTagName('span')[2]
     expect(loadingCounter.className).toContain('LoadingCounter')
     expect(loadingCounter.textContent).toBe('')
   })
+
   it('renders a visually hidden h2 heading for screen readers when aria-label is present', () => {
     const {getByRole} = render(<ResponsiveUnderlineNav />)
     const heading = getByRole('heading', {name: 'Repository navigation'})
@@ -157,6 +166,7 @@ describe('UnderlineNav', () => {
     expect(heading.className).toContain('VisuallyHidden')
     expect(heading.textContent).toBe('Repository navigation')
   })
+
   it('throws an error when there are multiple items that have aria-current', () => {
     const spy = jest.spyOn(console, 'error').mockImplementation()
     expect(() => {
@@ -186,6 +196,22 @@ describe('UnderlineNav', () => {
     // We are expecting a left value back, that way we know the `getAnchoredPosition` ran.
     expect(results).toEqual(expect.objectContaining({left: 0}))
   })
+
+  it('should support icons passed in as an element', () => {
+    render(
+      <UnderlineNav aria-label="Repository">
+        <UnderlineNav.Item aria-current="page" icon={<CodeIcon aria-label="Page one icon" />}>
+          Page one
+        </UnderlineNav.Item>
+        <UnderlineNav.Item icon={<IssueOpenedIcon aria-label="Page two icon" />}>Page two</UnderlineNav.Item>
+        <UnderlineNav.Item icon={<GitPullRequestIcon aria-label="Page three icon" />}>Page three</UnderlineNav.Item>
+      </UnderlineNav>,
+    )
+
+    expect(screen.getByLabelText('Page one icon')).toBeInTheDocument()
+    expect(screen.getByLabelText('Page two icon')).toBeInTheDocument()
+    expect(screen.getByLabelText('Page three icon')).toBeInTheDocument()
+  })
 })
 
 describe('Keyboard Navigation', () => {

packages/react/src/UnderlineNav/UnderlineNavItem.tsx

@@ -38,7 +38,7 @@ export type UnderlineNavItemProps = {
   /**
    *  Icon before the text
    */
-  icon?: React.FunctionComponent<IconProps>
+  icon?: React.FunctionComponent<IconProps> | React.ReactElement
   /**
    * Renders `UnderlineNav.Item` as given component i.e. react-router's Link
    **/

packages/react/src/internal/components/UnderlineTabbedInterface.tsx

@@ -1,6 +1,7 @@
 // Used for UnderlineNav and UnderlinePanels components
 
 import React, {forwardRef, type FC, type PropsWithChildren} from 'react'
+import {isElement} from 'react-is'
 import type {IconProps} from '@primer/octicons-react'
 import styled, {keyframes} from 'styled-components'
 import CounterLabel from '../../CounterLabel'
@@ -193,7 +194,7 @@ export type UnderlineItemProps = {
   iconsVisible?: boolean
   loadingCounters?: boolean
   counter?: number | string
-  icon?: FC<IconProps>
+  icon?: FC<IconProps> | React.ReactElement
   id?: string
 } & SxProp
 
@@ -213,11 +214,7 @@ export const UnderlineItem = forwardRef(
   ) => {
     return (
       <StyledUnderlineItem ref={forwardedRef} as={as} sx={sxProp} {...rest}>
-        {iconsVisible && Icon && (
-          <span data-component="icon">
-            <Icon />
-          </span>
-        )}
+        {iconsVisible && Icon && <span data-component="icon">{isElement(Icon) ? Icon : <Icon />}</span>}
         {children && (
           <span data-component="text" data-content={children}>
             {children}