SideNav

A named group of links with one of them active. The primitive owns the navigation label and aria-current — not an agreement to remember them.

When to use it

A side menu that switches the content beside it, with one item currently shown.
The page has more than one navigation (guides and components, sections and subsections). Each gets its own label, so a screen reader can tell them apart.

When not to use it

The items switch nothing and are only listed. Then it is a list — IngotList with variant="plain".
The menu needs extra behaviour: collapsible groups, icons, overflow into a "more" control. This primitive is deliberately bare; a richer menu should stay with the screen until a second caller asks for it.
The item triggers an action, not navigation. A link that goes nowhere is a button — Button.

Properties

label: string — The navigation's aria-label and the visible group heading. Required.
items: readonly IngotNavItem[] — The menu items. Item properties are in the table below.
testId: string — data-testid of the nav.