Add expand to NavList

[TylerJDev]

Adds new component NavList.ShowMoreItem, allows native support for "expanding" content within a NavList.

Closeshttps://github.com/github/primer/issues/2637

Proposed API

Basic example:

exportconstWithExpand=()=>{constitems=[{href: '#',text: 'Item 4'},{href: '#',text: 'Item 5'},{href: '#',text: 'Item 6'},{href: '#',text: 'Item 7'},{href: '#',text: 'Item 8'},{href: '#',text: 'Item 9'},]return(<NavList><NavList.Itemhref="#"aria-current="page">
Item 1
</NavList.Item><NavList.Itemhref="#">Item 2</NavList.Item><NavList.Itemhref="#">Item 3</NavList.Item><NavList.GroupExpandlabel="Show more"items={items}/></NavList>)}

Multiple expands:

exportconstExpandWithPages=()=>{constitems=[{href: '#',text: 'Item 4'},{href: '#',text: 'Item 5'},{href: '#',text: 'Item 6'},{href: '#',text: 'Item 7'},{href: '#',text: 'Item 8'},{href: '#',text: 'Item 9'},]return(<NavList><NavList.Itemhref="#"aria-current="page">
Item 1
</NavList.Item><NavList.Itemhref="#">Item 2</NavList.Item><NavList.Itemhref="#">Item 3</NavList.Item><NavList.GroupExpandpages={2}label="Show more"items={items}/></NavList>)}

Group example (storybook)

Changelog

New

• Adds new component NavList.ShowMoreItem

Rollout strategy

• Patch release
• Minor release
• Major release; if selected, include a written rollout or migration plan
• None; if selected, include a brief description as to why

Testing & Reviewing

Merge checklist

• Added/updated tests
• Added/updated documentation
• Added/updated previews (Storybook)
• Changes are SSR compatible
• Tested in Chrome
• Tested in Firefox
• Tested in Safari
• Tested in Edge
• (GitHub staff only) Integration tests pass at github/github (Learn more about how to run integration tests)

[changeset-bot]

🦋 Changeset detected

Latest commit: d22f63f

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@primer/react	Minor

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[github-actions]

size-limit report 📦

Path	Size
packages/react/dist/browser.esm.js	106.02 KB (+0.24% 🔺)
packages/react/dist/browser.umd.js	106.33 KB (+0.15% 🔺)

[TylerJDev]

I would love to not have to express this in GroupItems, as we don't want consumers adding this data-* attribute themselves. The only reason I have it here is so TS doesn't yell at me for adding it in itemArr['data-expand-focus-target'] = focusTarget.

[TylerJDev]

Have to utilize this to account for both ActionList and NavList FFs.

[TylerJDev]

@joshblack, should be ready for another review! I moved towards the data API that you suggested, and it seems to work great! Let me know if you have any suggestions or ways to improve it! 😁

[joshblack]

Congrats on putting this together! Just left a comment but approving since it's non-blocking 👍

[primer-integration]

👋 Hi from github/github! Your integration PR is ready: https://github.com/github/github/pull/363691

[primer-integration]

🟢 golden-jobs completed with status success.

[github-actions]

👋 Hi, there are new commits since the last successful integration test. We recommend running the integration workflow once more, unless you are sure the new changes do not affect github/github. Thanks!