docs/components/release-notes/GHAEReleaseNotes.tsx

import { useState } from 'react'
import cx from 'classnames'
import { ChevronDownIcon } from '@primer/octicons-react'
import { GHAEReleaseNotePatch } from './GHAEReleaseNotePatch'
import { GHAEReleaseNotesContextT } from './types'

type GitHubAEProps = {
  context: GHAEReleaseNotesContextT
}
export function GHAEReleaseNotes({ context }: GitHubAEProps) {
  const { releaseNotes, releases, currentVersion } = context
  const [focusedPatch, setFocusedPatch] = useState('')

  return (
    <div className="d-flex">
      <article className="min-width-0 flex-1">
        <div className="d-flex flex-items-center flex-justify-between color-bg-primary px-5 py-2">
          <div></div>
          <h1 className="f4 py-3 m-0">{currentVersion.planTitle} release notes</h1>
          <div></div>
        </div>

        <div className="markdown-body">
          {releaseNotes.map((patch) => {
            return (
              <GHAEReleaseNotePatch
                key={patch.version}
                patch={patch}
                didEnterView={() => setFocusedPatch(patch.version)}
              />
            )
          })}
        </div>
      </article>

      <aside
        className="markdown-body position-sticky top-0 d-none d-md-block border-left no-print color-bg-primary flex-shrink-0"
        style={{ width: 260, height: '100vh' }}
      >
        <nav className="height-full overflow-auto">
          <ul className="list-style-none pl-0 text-bold">
            {releases.map((release) => {
              return (
                <li key={release.version} className="border-bottom">
                  <details
                    className="my-0 details-reset release-notes-version-picker"
                    aria-current="page"
                    open
                  >
                    <summary className="px-3 py-4 my-0 d-flex flex-items-center flex-justify-between">
                      {release.version}
                      <div className="d-flex">
                        <span className="color-text-tertiary text-mono text-small text-normal mr-1">
                          {release.patches.length} releases
                        </span>
                        <ChevronDownIcon />
                      </div>
                    </summary>
                    <ul className="color-bg-tertiary border-top list-style-none py-4 px-0 my-0">
                      {release.patches.map((patch) => {
                        const isActive = patch.version === focusedPatch
                        return (
                          <li
                            key={patch.version}
                            className={cx(
                              'js-release-notes-patch-link px-3 my-0 py-1',
                              isActive && 'selected'
                            )}
                          >
                            <a
                              href={`#${patch.date}`}
                              className="d-flex flex-items-center flex-justify-between"
                            >
                              {patch.friendlyDate}
                            </a>
                          </li>
                        )
                      })}
                    </ul>
                  </details>
                </li>
              )
            })}
          </ul>
        </nav>
      </aside>
    </div>
  )
}