Sidebar

<!-- Sidebar – Semantic HTML -->
<nav class="sidebar" aria-label="Main navigation">
  <div class="sidebar-header">
    <img src="/logo.svg" alt="App Logo" width="32" height="32" />
    <span class="sidebar-title">Dashboard</span>
  </div>

  <ul class="sidebar-nav">
    <li class="sidebar-section-label">Analytics</li>
    <li>
      <a href="/dashboard" class="sidebar-item active" aria-current="page">
        <svg class="sidebar-icon" aria-hidden="true"><!-- chart icon --></svg>
        <span class="sidebar-label">Overview</span>
      </a>
    </li>
    <li>
      <a href="/reports" class="sidebar-item">
        <svg class="sidebar-icon" aria-hidden="true"><!-- report icon --></svg>
        <span class="sidebar-label">Reports</span>
      </a>
    </li>
    <li class="sidebar-section-label">Management</li>
    <li>
      <button class="sidebar-item" aria-expanded="false" aria-controls="sub-users">
        <svg class="sidebar-icon" aria-hidden="true"><!-- users icon --></svg>
        <span class="sidebar-label">Users</span>
        <svg class="sidebar-chevron" aria-hidden="true"><!-- chevron --></svg>
      </button>
      <ul id="sub-users" class="sidebar-submenu" hidden>
        <li><a href="/users/all" class="sidebar-item">All Users</a></li>
        <li><a href="/users/roles" class="sidebar-item">Roles</a></li>
      </ul>
    </li>
  </ul>

  <div class="sidebar-footer">
    <a href="/settings" class="sidebar-item">
      <svg class="sidebar-icon" aria-hidden="true"><!-- settings icon --></svg>
      <span class="sidebar-label">Settings</span>
    </a>
  </div>
</nav>

<style>
.sidebar {
  width: var(--sidebar-width, 256px);
  height: 100vh;
  position: fixed;
  top: 0;
  left: 0;
  background: var(--sidebar-bg, #f9fafb);
  border-right: 1px solid var(--sidebar-border-color, #e5e7eb);
  display: flex;
  flex-direction: column;
  transition: width var(--sidebar-transition-duration, 200ms) ease;
  overflow: hidden;
}

.sidebar.collapsed {
  width: var(--sidebar-width-collapsed, 64px);
}

.sidebar.collapsed .sidebar-label,
.sidebar.collapsed .sidebar-title,
.sidebar.collapsed .sidebar-section-label,
.sidebar.collapsed .sidebar-chevron {
  display: none;
}

.sidebar-nav {
  list-style: none;
  padding: 0.5rem;
  margin: 0;
  flex: 1;
  overflow-y: auto;
}

.sidebar-item {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.5rem var(--sidebar-item-padding-x, 0.75rem);
  border-radius: var(--sidebar-item-radius, 6px);
  color: var(--sidebar-item-color, #6b7280);
  text-decoration: none;
  cursor: pointer;
  border: none;
  background: none;
  width: 100%;
  font: inherit;
  height: var(--sidebar-item-height, 40px);
}

.sidebar-item:hover {
  background: var(--sidebar-item-bg-hover, #f3f4f6);
  color: var(--sidebar-item-color-hover, #111827);
}

.sidebar-item.active {
  background: var(--sidebar-item-bg-active, #eff6ff);
  color: var(--sidebar-item-color-active, #2563eb);
  font-weight: 600;
}

.sidebar-submenu {
  list-style: none;
  padding-left: 1rem;
  margin: 0;
}
</style>

interface SidebarItem {
  id: string;
  label: string;
  href?: string;
  icon: React.ReactNode;
  badge?: string | number;
  children?: SidebarItem[];
}

interface SidebarProps {
  items: SidebarItem[];
  activeItem?: string;
  collapsed?: boolean;
  onCollapsedChange?: (collapsed: boolean) => void;
  onNavigate?: (href: string) => void;
  header?: React.ReactNode;
  footer?: React.ReactNode;
}

function Sidebar({ items, activeItem, collapsed = false, onCollapsedChange, onNavigate, header, footer }: SidebarProps) {
  const [expandedGroups, setExpandedGroups] = React.useState<Set<string>>(new Set());

  const toggleGroup = (id: string) => {
    setExpandedGroups((prev) => {
      const next = new Set(prev);
      next.has(id) ? next.delete(id) : next.add(id);
      return next;
    });
  };

  const renderItem = (item: SidebarItem, depth = 0) => {
    const isActive = item.id === activeItem;
    const hasChildren = item.children && item.children.length > 0;
    const isExpanded = expandedGroups.has(item.id);

    if (hasChildren) {
      return (
        <li key={item.id}>
          <button
            className={`sidebar-item ${isActive ? "active" : ""}`}
            onClick={() => toggleGroup(item.id)}
            aria-expanded={isExpanded}
            aria-controls={`sub-${item.id}`}
            style={{ paddingLeft: `${0.75 + depth * 1}rem` }}
          >
            {item.icon}
            {!collapsed && <span className="sidebar-label">{item.label}</span>}
            {!collapsed && <span className={`sidebar-chevron ${isExpanded ? "rotated" : ""}`}>›</span>}
          </button>
          {isExpanded && (
            <ul id={`sub-${item.id}`} className="sidebar-submenu">
              {item.children!.map((child) => renderItem(child, depth + 1))}
            </ul>
          )}
        </li>
      );
    }

    return (
      <li key={item.id}>
        <a
          href={item.href}
          className={`sidebar-item ${isActive ? "active" : ""}`}
          aria-current={isActive ? "page" : undefined}
          onClick={(e) => {
            if (onNavigate && item.href) {
              e.preventDefault();
              onNavigate(item.href);
            }
          }}
          style={{ paddingLeft: `${0.75 + depth * 1}rem` }}
        >
          {item.icon}
          {!collapsed && <span className="sidebar-label">{item.label}</span>}
          {item.badge != null && <span className="sidebar-badge">{item.badge}</span>}
        </a>
      </li>
    );
  };

  return (
    <nav className={`sidebar ${collapsed ? "collapsed" : ""}`} aria-label="Main navigation">
      {header && <div className="sidebar-header">{header}</div>}
      <ul className="sidebar-nav">{items.map((item) => renderItem(item))}</ul>
      {footer && <div className="sidebar-footer">{footer}</div>}
      <button
        className="sidebar-collapse-toggle"
        onClick={() => onCollapsedChange?.(!collapsed)}
        aria-label={collapsed ? "Expand sidebar" : "Collapse sidebar"}
      >
        {collapsed ? "»" : "«"}
      </button>
    </nav>
  );
}

// Usage
<Sidebar
  collapsed={false}
  onCollapsedChange={setCollapsed}
  activeItem="overview"
  header={<Logo />}
  footer={<UserMenu />}
  items={[
    { id: "overview", label: "Overview", href: "/dashboard", icon: <ChartIcon /> },
    { id: "reports", label: "Reports", href: "/reports", icon: <ReportIcon /> },
    {
      id: "users",
      label: "Users",
      icon: <UsersIcon />,
      children: [
        { id: "all-users", label: "All Users", href: "/users/all", icon: <ListIcon /> },
        { id: "roles", label: "Roles", href: "/users/roles", icon: <ShieldIcon /> },
      ],
    },
  ]}
  onNavigate={(href) => router.push(href)}
/>