Base UI

A collection of links and menus for website navigation.

import * as React from 'react';
import { NavigationMenu } from '@base-ui/react/navigation-menu';
import styles from './index.module.css';

export default function ExampleNavigationMenu() {
  return (
    <NavigationMenu.Root className={styles.Root}>
      <NavigationMenu.List className={styles.List}>
        <NavigationMenu.Item>
          <NavigationMenu.Trigger className={styles.Trigger}>
            Overview
            <NavigationMenu.Icon className={styles.Icon}>
              <ChevronDownIcon />
            </NavigationMenu.Icon>
          </NavigationMenu.Trigger>
          <NavigationMenu.Content className={styles.Content}>
            <ul className={styles.GridLinkList}>
              {overviewLinks.map((item) => (
                <li key={item.href}>
                  <Link className={styles.LinkCard} href={item.href}>
                    <h3 className={styles.LinkTitle}>{item.title}</h3>
                    <p className={styles.LinkDescription}>{item.description}</p>
                  </Link>
                </li>
              ))}
            </ul>
          </NavigationMenu.Content>
        </NavigationMenu.Item>

        <NavigationMenu.Item>
          <NavigationMenu.Trigger className={styles.Trigger}>
            Handbook
            <NavigationMenu.Icon className={styles.Icon}>
              <ChevronDownIcon />
            </NavigationMenu.Icon>
          </NavigationMenu.Trigger>
          <NavigationMenu.Content className={styles.Content}>
            <ul className={styles.FlexLinkList}>
              {handbookLinks.map((item) => (
                <li key={item.href}>
                  <Link className={styles.LinkCard} href={item.href}>
                    <h3 className={styles.LinkTitle}>{item.title}</h3>
                    <p className={styles.LinkDescription}>{item.description}</p>
                  </Link>
                </li>
              ))}
            </ul>
          </NavigationMenu.Content>
        </NavigationMenu.Item>

        <NavigationMenu.Item>
          <Link className={styles.Trigger} href="https://github.com/mui/base-ui">
            GitHub
          </Link>
        </NavigationMenu.Item>
      </NavigationMenu.List>

      <NavigationMenu.Portal>
        <NavigationMenu.Positioner
          className={styles.Positioner}
          sideOffset={10}
          collisionPadding={{ top: 5, bottom: 5, left: 20, right: 20 }}
          collisionAvoidance={{ side: 'none' }}
        >
          <NavigationMenu.Popup className={styles.Popup}>
            <NavigationMenu.Arrow className={styles.Arrow}>
              <ArrowSvg />
            </NavigationMenu.Arrow>
            <NavigationMenu.Viewport className={styles.Viewport} />
          </NavigationMenu.Popup>
        </NavigationMenu.Positioner>
      </NavigationMenu.Portal>
    </NavigationMenu.Root>
  );
}

function Link(props: NavigationMenu.Link.Props) {
  return (
    <NavigationMenu.Link
      render={
        // Use the `render` prop to render your framework's Link component
        // for client-side routing.
        // e.g. `<NextLink href={props.href} />` instead of `<a />`.
        <a />
      }
      {...props}
    />
  );
}

function ChevronDownIcon(props: React.ComponentProps<'svg'>) {
  return (
    <svg width="10" height="10" viewBox="0 0 10 10" fill="none" {...props}>
      <path d="M1 3.5L5 7.5L9 3.5" stroke="currentcolor" strokeWidth="1.5" />
    </svg>
  );
}

function ArrowSvg(props: React.ComponentProps<'svg'>) {
  return (
    <svg width="20" height="10" viewBox="0 0 20 10" fill="none" {...props}>
      <path
        d="M9.66437 2.60207L4.80758 6.97318C4.07308 7.63423 3.11989 8 2.13172 8H0V10H20V8H18.5349C17.5468 8 16.5936 7.63423 15.8591 6.97318L11.0023 2.60207C10.622 2.2598 10.0447 2.25979 9.66437 2.60207Z"
        className={styles.ArrowFill}
      />
      <path
        d="M8.99542 1.85876C9.75604 1.17425 10.9106 1.17422 11.6713 1.85878L16.5281 6.22989C17.0789 6.72568 17.7938 7.00001 18.5349 7.00001L15.89 7L11.0023 2.60207C10.622 2.2598 10.0447 2.2598 9.66436 2.60207L4.77734 7L2.13171 7.00001C2.87284 7.00001 3.58774 6.72568 4.13861 6.22989L8.99542 1.85876Z"
        className={styles.ArrowOuterStroke}
      />
      <path
        d="M10.3333 3.34539L5.47654 7.71648C4.55842 8.54279 3.36693 9 2.13172 9H0V8H2.13172C3.11989 8 4.07308 7.63423 4.80758 6.97318L9.66437 2.60207C10.0447 2.25979 10.622 2.2598 11.0023 2.60207L15.8591 6.97318C16.5936 7.63423 17.5468 8 18.5349 8H20V9H18.5349C17.2998 9 16.1083 8.54278 15.1901 7.71648L10.3333 3.34539Z"
        className={styles.ArrowInnerStroke}
      />
    </svg>
  );
}

const overviewLinks = [
  {
    href: '/react/overview/quick-start',    title: 'Quick Start',
    description: 'Install and assemble your first component.',
  },
  {
    href: '/react/overview/accessibility',
    title: 'Accessibility',
    description: 'Learn how we build accessible components.',
  },
  {
    href: '/react/overview/releases',
    title: 'Releases',
    description: 'See what’s new in the latest Base UI versions.',
  },
  {
    href: '/react/overview/about',
    title: 'About',
    description: 'Learn more about Base UI and our mission.',
  },
] as const;

const handbookLinks = [
  {
    href: '/react/handbook/styling',
    title: 'Styling',
    description:
      'Base UI components can be styled with plain CSS, Tailwind CSS, CSS-in-JS, or CSS Modules.',
  },
  {
    href: '/react/handbook/animation',
    title: 'Animation',
    description:
      'Base UI components can be animated with CSS transitions, CSS animations, or JavaScript libraries.',
  },
  {
    href: '/react/handbook/composition',
    title: 'Composition',
    description:
      'Base UI components can be replaced and composed with your own existing components.',
  },
] as const;

Anatomy

Import the component and assemble its parts:

Anatomy

import { NavigationMenu } from '@base-ui/react/navigation-menu';

<NavigationMenu.Root>
  <NavigationMenu.List>
    <NavigationMenu.Item>
      <NavigationMenu.Trigger>
        <NavigationMenu.Icon />
      </NavigationMenu.Trigger>
      <NavigationMenu.Content>
        <NavigationMenu.Link />
      </NavigationMenu.Content>
    </NavigationMenu.Item>
  </NavigationMenu.List>

  <NavigationMenu.Portal>
    <NavigationMenu.Backdrop />
    <NavigationMenu.Positioner>
      <NavigationMenu.Popup>
        <NavigationMenu.Arrow />
        <NavigationMenu.Viewport />
      </NavigationMenu.Popup>
    </NavigationMenu.Positioner>
  </NavigationMenu.Portal>
</NavigationMenu.Root>

Examples

Nested submenus

<NavigationMenu.Root> component can be nested within a higher-level <NavigationMenu.Content> part to create a multi-level navigation menu.

Nested inline submenus

For second-level navigation that should stay in the same panel, omit the nested <NavigationMenu.Portal> and render only List + Viewport with a defaultValue.

Custom links

The <NavigationMenu.Link> part can be customized to render the link from your framework using the render prop to enable client-side routing.

Next.js example

import NextLink from 'next/link';
import { NavigationMenu } from '@base-ui/react/navigation-menu';

function Link(props: NavigationMenu.Link.Props) {
  return (
    <NavigationMenu.Link
      render={<NextLink href={props.href} />}
      {...props}
    />
  );
}

Large menus

When you have large menu content that doesn’t fit in the viewport in some cases, you usually have two choices:

Compress the navigation menu content

You can change the layout of the navigation menu to render less content or be more compact by reducing the space it takes up. If your content is flexible, you can use the max-height property on .Popup to limit the height of the navigation menu to let it compress itself while preventing overflow.

Compact layout

.Content,
.Popup {
  max-height: var(--available-height);
}

Make the navigation menu scrollable

Scrollable layout

.Content,
.Popup {
  max-height: var(--available-height);
}

.Content {
  overflow-y: auto;
}

Native scrollbars are visible while transitioning content, so we recommend using the Scroll Area component instead of native scrollbars to keep them hidden, which also allows the Arrow to be centered correctly.

API reference

Root

Groups all parts of the navigation menu. Renders a <nav> element at the root, or <div> element when nested.

defaultValueValue | nullnull

Name: defaultValue
Description: The uncontrolled value of the item that should be initially selected.

To render a controlled navigation menu, use the value prop instead.
Type: Value | null | undefined
Default: null

valueValue | nullnull

Name: value
Description: The controlled value of the navigation menu item that should be currently open. When non-nullish, the menu will be open. When nullish, the menu will be closed.

To render an uncontrolled navigation menu, use the defaultValue prop instead.
Type: Value | null | undefined
Default: null

onValueChangefunction—

Name: onValueChange
Description: Callback fired when the value changes.
Type: | (( value: Value | null, eventDetails: NavigationMenu.Root.ChangeEventDetails, ) => void) | undefined

actionsRefReact.RefObject<NavigationMenu.Root.Actions | null>—

Name: actionsRef
Description: A ref to imperative actions.
Type: | React.RefObject<NavigationMenu.Root.Actions | null> | undefined

onOpenChangeCompletefunction—

Name: onOpenChangeComplete
Description: Event handler called after any animations complete when the navigation menu is closed.
Type: ((open: boolean) => void) | undefined

delaynumber50

Name: delay
Description: How long to wait before opening the navigation popup. Specified in milliseconds.
Type: number | undefined
Default: 50

closeDelaynumber50

Name: closeDelay
Description: How long to wait before closing the navigation popup. Specified in milliseconds.
Type: number | undefined
Default: 50

orientation'horizontal' | 'vertical''horizontal'

Name: orientation
Description: The orientation of the navigation menu.
Type: 'horizontal' | 'vertical' | undefined
Default: 'horizontal'

classNamestring | function—

Name: className
Description: CSS class applied to the element, or a function that returns a class based on the component’s state.
Type: | string | (( state: NavigationMenu.Root.State, ) => string | undefined) | undefined

styleReact.CSSProperties | function—

Name: style
Type: | React.CSSProperties | (( state: NavigationMenu.Root.State, ) => React.CSSProperties | undefined) | undefined

renderReactElement | function—

Name: render
Description: Allows you to replace the component’s HTML element with a different tag, or compose it with another component.

Accepts a ReactElement or a function that returns the element to render.
Type: | ReactElement | (( props: HTMLProps, state: NavigationMenu.Root.State, ) => ReactElement) | undefined

NavigationMenu.Root.PropsHide

Re-Export of Root props as NavigationMenuRootProps

NavigationMenu.Root.StateHide

type NavigationMenuRootState = {
  /** If `true`, the popup is open. */
  open: boolean;
  /** Whether the navigation menu is nested. */
  nested: boolean;
}

NavigationMenu.Root.ActionsHide

type NavigationMenuRootActions = { unmount: () => void }

NavigationMenu.Root.ChangeEventReasonHide

type NavigationMenuRootChangeEventReason =
  | 'trigger-press'
  | 'trigger-hover'
  | 'outside-press'
  | 'list-navigation'
  | 'focus-out'
  | 'escape-key'
  | 'link-press'
  | 'none'

NavigationMenu.Root.ChangeEventDetailsHide

type NavigationMenuRootChangeEventDetails = (
  | { reason: 'trigger-press'; event: MouseEvent | PointerEvent | TouchEvent | KeyboardEvent }
  | { reason: 'trigger-hover'; event: MouseEvent }
  | { reason: 'outside-press'; event: MouseEvent | PointerEvent | TouchEvent }
  | { reason: 'list-navigation'; event: KeyboardEvent }
  | { reason: 'focus-out'; event: KeyboardEvent | FocusEvent }
  | { reason: 'escape-key'; event: KeyboardEvent }
  | { reason: 'link-press'; event: MouseEvent | PointerEvent }
  | { reason: 'none'; event: Event }
) & {
  /** Cancels Base UI from handling the event. */
  cancel: () => void;
  /** Allows the event to propagate in cases where Base UI will stop the propagation. */
  allowPropagation: () => void;
  /** Indicates whether the event has been canceled. */
  isCanceled: boolean;
  /** Indicates whether the event is allowed to propagate. */
  isPropagationAllowed: boolean;
  /** The element that triggered the event, if applicable. */
  trigger: Element | undefined;
}

NavigationMenu.Root.ValueHide

type NavigationMenuRootValue<TValue = any> = TValue | null

List

Contains a list of navigation menu items. Renders a <ul> element.

classNamestring | function—

Name: className
Description: CSS class applied to the element, or a function that returns a class based on the component’s state.
Type: | string | (( state: NavigationMenu.List.State, ) => string | undefined) | undefined

styleReact.CSSProperties | function—

Name: style
Type: | React.CSSProperties | (( state: NavigationMenu.List.State, ) => React.CSSProperties | undefined) | undefined

renderReactElement | function—

Name: render
Description: Allows you to replace the component’s HTML element with a different tag, or compose it with another component.

Accepts a ReactElement or a function that returns the element to render.
Type: | ReactElement | (( props: HTMLProps, state: NavigationMenu.List.State, ) => ReactElement) | undefined

NavigationMenu.List.PropsHide

Re-Export of List props as NavigationMenuListProps

NavigationMenu.List.StateHide

type NavigationMenuListState = {
  /** If `true`, the popup is open. */
  open: boolean;
}

Item

An individual navigation menu item. Renders a <li> element.

valueany—

Name: value
Description: A unique value that identifies this navigation menu item. If no value is provided, a unique ID will be generated automatically. Use when controlling the navigation menu programmatically.
Type: any | undefined

classNamestring | function—

Name: className
Description: CSS class applied to the element, or a function that returns a class based on the component’s state.
Type: | string | (( state: NavigationMenu.Item.State, ) => string | undefined) | undefined

styleReact.CSSProperties | function—

Name: style
Type: | React.CSSProperties | (( state: NavigationMenu.Item.State, ) => React.CSSProperties | undefined) | undefined

renderReactElement | function—

Name: render
Description: Allows you to replace the component’s HTML element with a different tag, or compose it with another component.

Accepts a ReactElement or a function that returns the element to render.
Type: | ReactElement | (( props: HTMLProps, state: NavigationMenu.Item.State, ) => ReactElement) | undefined

NavigationMenu.Item.PropsHide

Re-Export of Item props as NavigationMenuItemProps

NavigationMenu.Item.StateHide

type NavigationMenuItemState = {}

Trigger

Opens the navigation menu popup when hovered or clicked, revealing the associated content. Renders a <button> element.

nativeButtonbooleantrue

Name: nativeButton
Description: Whether the component renders a native <button> element when replacing it via the render prop. Set to false if the rendered element is not a button (for example, <div>).
Type: boolean | undefined
Default: true

classNamestring | function—

Name: className
Description: CSS class applied to the element, or a function that returns a class based on the component’s state.
Type: | string | (( state: NavigationMenu.Trigger.State, ) => string | undefined) | undefined

styleReact.CSSProperties | function—

Name: style
Type: | React.CSSProperties | (( state: NavigationMenu.Trigger.State, ) => React.CSSProperties | undefined) | undefined

renderReactElement | function—

Name: render
Description: Allows you to replace the component’s HTML element with a different tag, or compose it with another component.

Accepts a ReactElement or a function that returns the element to render.
Type: | ReactElement | (( props: HTMLProps, state: NavigationMenu.Trigger.State, ) => ReactElement) | undefined

data-popup-open

Present when the corresponding navigation menu is open.

data-pressed

Present when the trigger is pressed.

Attribute	Description	-
`data-popup-open`	Present when the corresponding navigation menu is open.
`data-pressed`	Present when the trigger is pressed.

NavigationMenu.Trigger.PropsHide

Re-Export of Trigger props as NavigationMenuTriggerProps

NavigationMenu.Trigger.StateHide

type NavigationMenuTriggerState = {
  /** If `true`, the popup is open and the item is active. */
  open: boolean;
}

Icon

An icon that indicates that the trigger button opens a menu.

classNamestring | function—

Name: className
Description: CSS class applied to the element, or a function that returns a class based on the component’s state.
Type: | string | (( state: NavigationMenu.Icon.State, ) => string | undefined) | undefined

styleReact.CSSProperties | function—

Name: style
Type: | React.CSSProperties | (( state: NavigationMenu.Icon.State, ) => React.CSSProperties | undefined) | undefined

renderReactElement | function—

Name: render
Description: Allows you to replace the component’s HTML element with a different tag, or compose it with another component.

Accepts a ReactElement or a function that returns the element to render.
Type: | ReactElement | (( props: HTMLProps, state: NavigationMenu.Icon.State, ) => ReactElement) | undefined

NavigationMenu.Icon.PropsHide

Re-Export of Icon props as NavigationMenuIconProps

NavigationMenu.Icon.StateHide

type NavigationMenuIconState = {
  /** Whether the navigation menu is open and the item is active. */
  open: boolean;
}

Content

A container for the content of the navigation menu item that is moved into the popup when the item is active. Renders a <div> element.

classNamestring | function—

Name: className
Description: CSS class applied to the element, or a function that returns a class based on the component’s state.
Type: | string | (( state: NavigationMenu.Content.State, ) => string | undefined) | undefined

styleReact.CSSProperties | function—

Name: style
Type: | React.CSSProperties | (( state: NavigationMenu.Content.State, ) => React.CSSProperties | undefined) | undefined

keepMountedbooleanfalse

Name: keepMounted
Description: Whether to keep the content mounted in the DOM while the popup is closed. Ensures the content is present during server-side rendering for web crawlers.
Type: boolean | undefined
Default: false

renderReactElement | function—

Name: render
Description: Allows you to replace the component’s HTML element with a different tag, or compose it with another component.

Accepts a ReactElement or a function that returns the element to render.
Type: | ReactElement | (( props: HTMLProps, state: NavigationMenu.Content.State, ) => ReactElement) | undefined

data-open

Present when the popup is open.

data-closed

Present when the popup is closed.

data-activation-direction

Which direction another trigger was activated from.

data-starting-style

Present when the content is animating in.

data-ending-style

Present when the content is animating out.

Attribute	Description	-
`data-open`	Present when the popup is open.
`data-closed`	Present when the popup is closed.
`data-activation-direction`	Which direction another trigger was activated from.
`data-starting-style`	Present when the content is animating in.
`data-ending-style`	Present when the content is animating out.

NavigationMenu.Content.PropsHide

Re-Export of Content props as NavigationMenuContentProps

NavigationMenu.Content.StateHide

type NavigationMenuContentState = {
  /** If `true`, the component is open. */
  open: boolean;
  /** The transition status of the component. */
  transitionStatus: TransitionStatus;
  /** The direction of the activation. */
  activationDirection: 'left' | 'right' | 'up' | 'down' | null;
}

Link

A link in the navigation menu that can be used to navigate to a different page or section. Renders an <a> element.

closeOnClickbooleanfalse

Name: closeOnClick
Description: Whether to close the navigation menu when the link is clicked.
Type: boolean | undefined
Default: false

activebooleanfalse

Name: active
Description: Whether the link is the currently active page.
Type: boolean | undefined
Default: false

classNamestring | function—

Name: className
Description: CSS class applied to the element, or a function that returns a class based on the component’s state.
Type: | string | (( state: NavigationMenu.Link.State, ) => string | undefined) | undefined

styleReact.CSSProperties | function—

Name: style
Type: | React.CSSProperties | (( state: NavigationMenu.Link.State, ) => React.CSSProperties | undefined) | undefined

renderReactElement | function—

Name: render
Description: Allows you to replace the component’s HTML element with a different tag, or compose it with another component.

Accepts a ReactElement or a function that returns the element to render.
Type: | ReactElement | (( props: HTMLProps, state: NavigationMenu.Link.State, ) => ReactElement) | undefined

data-active

Present when the link is the currently active page.

Attribute	Description	-
`data-active`	Present when the link is the currently active page.

NavigationMenu.Link.PropsHide

Re-Export of Link props as NavigationMenuLinkProps

NavigationMenu.Link.StateHide

type NavigationMenuLinkState = {
  /** Whether the link is the currently active page. */
  active: boolean;
}

Backdrop

A backdrop for the navigation menu popup. Renders a <div> element.

classNamestring | function—

Name: className
Description: CSS class applied to the element, or a function that returns a class based on the component’s state.
Type: | string | (( state: NavigationMenu.Backdrop.State, ) => string | undefined) | undefined

styleReact.CSSProperties | function—

Name: style
Type: | React.CSSProperties | (( state: NavigationMenu.Backdrop.State, ) => React.CSSProperties | undefined) | undefined

renderReactElement | function—

Name: render
Description: Allows you to replace the component’s HTML element with a different tag, or compose it with another component.

Accepts a ReactElement or a function that returns the element to render.
Type: | ReactElement | (( props: HTMLProps, state: NavigationMenu.Backdrop.State, ) => ReactElement) | undefined

data-open

Present when the popup is open.

data-closed

Present when the popup is closed.

data-starting-style

Present when the popup is animating in.

data-ending-style

Present when the popup is animating out.

Attribute	Description	-
`data-open`	Present when the popup is open.
`data-closed`	Present when the popup is closed.
`data-starting-style`	Present when the popup is animating in.
`data-ending-style`	Present when the popup is animating out.

NavigationMenu.Backdrop.PropsHide

Re-Export of Backdrop props as NavigationMenuBackdropProps

NavigationMenu.Backdrop.StateHide

type NavigationMenuBackdropState = {
  /** If `true`, the popup is open. */
  open: boolean;
  /** The transition status of the popup. */
  transitionStatus: TransitionStatus;
}

Portal

A portal element that moves the popup to a different part of the DOM. By default, the portal element is appended to <body>. Renders a <div> element.

containerUnion—

Name: container
Description: A parent element to render the portal element into.
Type: | HTMLElement | ShadowRoot | React.RefObject<HTMLElement | ShadowRoot | null> | null | undefined

classNamestring | function—

Name: className
Description: CSS class applied to the element, or a function that returns a class based on the component’s state.
Type: | string | (( state: NavigationMenu.Portal.State, ) => string | undefined) | undefined

styleReact.CSSProperties | function—

Name: style
Type: | React.CSSProperties | (( state: NavigationMenu.Portal.State, ) => React.CSSProperties | undefined) | undefined

keepMountedbooleanfalse

Name: keepMounted
Description: Whether to keep the portal mounted in the DOM while the popup is hidden.
Type: boolean | undefined
Default: false

renderReactElement | function—

Name: render
Description: Allows you to replace the component’s HTML element with a different tag, or compose it with another component.

Accepts a ReactElement or a function that returns the element to render.
Type: | ReactElement | (( props: HTMLProps, state: NavigationMenu.Portal.State, ) => ReactElement) | undefined

NavigationMenu.Portal.PropsHide

Re-Export of Portal props as NavigationMenuPortalProps

NavigationMenu.Portal.StateHide

type NavigationMenuPortalState = {}

Positioner

Positions the navigation menu against the currently active trigger. Renders a <div> element.

disableAnchorTrackingbooleanfalse

Name: disableAnchorTracking
Description: Whether to disable the popup from tracking any layout shift of its positioning anchor.
Type: boolean | undefined
Default: false

alignAlign'center'

Name: align
Description: How to align the popup relative to the specified side.
Type: 'start' | 'center' | 'end' | undefined
Default: 'center'

alignOffsetnumber | OffsetFunction0

Name: alignOffset
Description: Additional offset along the alignment axis in pixels. Also accepts a function that returns the offset to read the dimensions of the anchor and positioner elements, along with its side and alignment.

The function takes a data object parameter with the following properties:

data.anchor: the dimensions of the anchor element with properties width and height.

data.positioner: the dimensions of the positioner element with properties width and height.

data.side: which side of the anchor element the positioner is aligned against.

data.align: how the positioner is aligned relative to the specified side.
Type: | number | ((data: { side: | 'top' | 'bottom' | 'left' | 'right' | 'inline-end' | 'inline-start'; align: 'start' | 'center' | 'end'; anchor: { width: number; height: number }; positioner: { width: number; height: number }; }) => number) | undefined
Default: 0
Example: <Positioner alignOffset={({ side, align, anchor, positioner }) => { return side === 'top' || side === 'bottom' ? anchor.width : anchor.height; }} />

sideSide'bottom'

Name: side
Description: Which side of the anchor element to align the popup against. May automatically change to avoid collisions.
Type: | 'top' | 'bottom' | 'left' | 'right' | 'inline-end' | 'inline-start' | undefined
Default: 'bottom'

sideOffsetnumber | OffsetFunction0

Name: sideOffset
Description: Distance between the anchor and the popup in pixels. Also accepts a function that returns the distance to read the dimensions of the anchor and positioner elements, along with its side and alignment.

The function takes a data object parameter with the following properties:

data.anchor: the dimensions of the anchor element with properties width and height.

data.positioner: the dimensions of the positioner element with properties width and height.

data.side: which side of the anchor element the positioner is aligned against.

data.align: how the positioner is aligned relative to the specified side.
Type: | number | ((data: { side: | 'top' | 'bottom' | 'left' | 'right' | 'inline-end' | 'inline-start'; align: 'start' | 'center' | 'end'; anchor: { width: number; height: number }; positioner: { width: number; height: number }; }) => number) | undefined
Default: 0
Example: <Positioner sideOffset={({ side, align, anchor, positioner }) => { return side === 'top' || side === 'bottom' ? anchor.height : anchor.width; }} />

arrowPaddingnumber5

Name: arrowPadding
Description: Minimum distance to maintain between the arrow and the edges of the popup.

Use it to prevent the arrow element from hanging out of the rounded corners of a popup.
Type: number | undefined
Default: 5

anchorUnion—

Name: anchor
Description: An element to position the popup against. By default, the popup will be positioned against the trigger.
Type: | Element | VirtualElement | React.RefObject<Element | null> | (() => Element | VirtualElement | null) | null | undefined

collisionAvoidanceCollisionAvoidance—

Name: collisionAvoidance
Description: Determines how to handle collisions when positioning the popup.

side controls overflow on the preferred placement axis (top/bottom or left/right):

'flip': keep the requested side when it fits; otherwise try the opposite side (top and bottom, or left and right).

'shift': never change side; keep the requested side and move the popup within the clipping boundary so it stays visible.

'none': do not correct side-axis overflow.

align controls overflow on the alignment axis (start/center/end):

'flip': keep side, but swap start and end when the requested alignment overflows.

'shift': keep side and requested alignment, then nudge the popup along the alignment axis to fit.

'none': do not correct alignment-axis overflow.

fallbackAxisSide controls fallback behavior on the perpendicular axis when the preferred axis cannot fit:

'start': allow perpendicular fallback and try the logical start side first (top before bottom, or left before right in LTR).

'end': allow perpendicular fallback and try the logical end side first (bottom before top, or right before left in LTR).

'none': do not fallback to the perpendicular axis.

When side is 'shift', explicitly setting align only supports 'shift' or 'none'. If align is omitted, it defaults to 'flip'.
Type: CollisionAvoidance | undefined
Example: <Positioner collisionAvoidance={{ side: 'shift', align: 'shift', fallbackAxisSide: 'none', }} />

collisionBoundaryBoundary'clipping-ancestors'

Name: collisionBoundary
Description: An element or a rectangle that delimits the area that the popup is confined to.
Type: Boundary | undefined
Default: 'clipping-ancestors'

collisionPaddingPadding5

Name: collisionPadding
Description: Additional space to maintain from the edge of the collision boundary.
Type: Padding | undefined
Default: 5

stickybooleanfalse

Name: sticky
Description: Whether to maintain the popup in the viewport after the anchor element was scrolled out of view.
Type: boolean | undefined
Default: false

positionMethod'absolute' | 'fixed''absolute'

Name: positionMethod
Description: Determines which CSS position property to use.
Type: 'absolute' | 'fixed' | undefined
Default: 'absolute'

classNamestring | function—

Name: className
Description: CSS class applied to the element, or a function that returns a class based on the component’s state.
Type: | string | (( state: NavigationMenu.Positioner.State, ) => string | undefined) | undefined

styleReact.CSSProperties | function—

Name: style
Type: | React.CSSProperties | (( state: NavigationMenu.Positioner.State, ) => React.CSSProperties | undefined) | undefined

renderReactElement | function—

Name: render
Description: Allows you to replace the component’s HTML element with a different tag, or compose it with another component.

Accepts a ReactElement or a function that returns the element to render.
Type: | ReactElement | (( props: HTMLProps, state: NavigationMenu.Positioner.State, ) => ReactElement) | undefined

data-open

Present when the popup is open.

data-closed

Present when the popup is closed.

data-anchor-hidden

Present when the anchor is hidden.

data-align

Indicates how the popup is aligned relative to the specified side.

data-instant

Present if animations should be instant.

data-side

Indicates which side the popup is positioned relative to the trigger.

Attribute	Description	-
`data-open`	Present when the popup is open.
`data-closed`	Present when the popup is closed.
`data-anchor-hidden`	Present when the anchor is hidden.
`data-align`	Indicates how the popup is aligned relative to the specified side.
`data-instant`	Present if animations should be instant.
`data-side`	Indicates which side the popup is positioned relative to the trigger.

--anchor-height

The anchor’s height.

--anchor-width

The anchor’s width.

--available-height

The available height between the trigger and the edge of the viewport.

--available-width

The available width between the trigger and the edge of the viewport.

--positioner-height

The fixed height of the positioner element.

--positioner-width

The fixed width of the positioner element.

--transform-origin

The coordinates that this element is anchored to. Used for animations and transitions.

CSS Variable	Description	-
`--anchor-height`	The anchor’s height.
`--anchor-width`	The anchor’s width.
`--available-height`	The available height between the trigger and the edge of the viewport.
`--available-width`	The available width between the trigger and the edge of the viewport.
`--positioner-height`	The fixed height of the positioner element.
`--positioner-width`	The fixed width of the positioner element.
`--transform-origin`	The coordinates that this element is anchored to. Used for animations and transitions.

NavigationMenu.Positioner.PropsHide

Re-Export of Positioner props as NavigationMenuPositionerProps

NavigationMenu.Positioner.StateHide

type NavigationMenuPositionerState = {
  /** Whether the navigation menu is currently open. */
  open: boolean;
  /** The side of the anchor the component is placed on. */
  side: 'top' | 'bottom' | 'left' | 'right' | 'inline-end' | 'inline-start';
  /** The alignment of the component relative to the anchor. */
  align: 'start' | 'center' | 'end';
  /** Whether the anchor element is hidden. */
  anchorHidden: boolean;
  /** Whether CSS transitions should be disabled. */
  instant: boolean;
}

A container for the navigation menu contents. Renders a <nav> element.

classNamestring | function—

Name: className
Description: CSS class applied to the element, or a function that returns a class based on the component’s state.
Type: | string | (( state: NavigationMenu.Popup.State, ) => string | undefined) | undefined

styleReact.CSSProperties | function—

Name: style
Type: | React.CSSProperties | (( state: NavigationMenu.Popup.State, ) => React.CSSProperties | undefined) | undefined

renderReactElement | function—

Name: render
Description: Allows you to replace the component’s HTML element with a different tag, or compose it with another component.

Accepts a ReactElement or a function that returns the element to render.
Type: | ReactElement | (( props: HTMLProps, state: NavigationMenu.Popup.State, ) => ReactElement) | undefined

data-open

Present when the popup is open.

data-closed

Present when the popup is closed.

data-align

Indicates how the popup is aligned relative to the specified side.

data-side

Indicates which side the popup is positioned relative to the trigger.

data-starting-style

Present when the popup is animating in.

data-ending-style

Present when the popup is animating out.

Attribute	Description	-
`data-open`	Present when the popup is open.
`data-closed`	Present when the popup is closed.
`data-align`	Indicates how the popup is aligned relative to the specified side.
`data-side`	Indicates which side the popup is positioned relative to the trigger.
`data-starting-style`	Present when the popup is animating in.
`data-ending-style`	Present when the popup is animating out.

--popup-height

The fixed height of the popup element.

--popup-width

The fixed width of the popup element.

CSS Variable	Description	-
`--popup-height`	The fixed height of the popup element.
`--popup-width`	The fixed width of the popup element.

NavigationMenu.Popup.StateHide

type NavigationMenuPopupState = {
  /** If `true`, the popup is open. */
  open: boolean;
  /** The transition status of the popup. */
  transitionStatus: TransitionStatus;
  /** The side of the anchor the popup is positioned on. */
  side: 'top' | 'bottom' | 'left' | 'right' | 'inline-end' | 'inline-start';
  /** The alignment of the popup relative to the anchor. */
  align: 'start' | 'center' | 'end';
  /** Whether the anchor element is hidden. */
  anchorHidden: boolean;
}

Viewport

The clipping viewport of the navigation menu’s current content. Renders a <div> element.

classNamestring | function—

Name: className
Description: CSS class applied to the element, or a function that returns a class based on the component’s state.
Type: | string | (( state: NavigationMenu.Viewport.State, ) => string | undefined) | undefined

styleReact.CSSProperties | function—

Name: style
Type: | React.CSSProperties | (( state: NavigationMenu.Viewport.State, ) => React.CSSProperties | undefined) | undefined

renderReactElement | function—

Name: render
Description: Allows you to replace the component’s HTML element with a different tag, or compose it with another component.

Accepts a ReactElement or a function that returns the element to render.
Type: | ReactElement | (( props: HTMLProps, state: NavigationMenu.Viewport.State, ) => ReactElement) | undefined

NavigationMenu.Viewport.PropsHide

Re-Export of Viewport props as NavigationMenuViewportProps

NavigationMenu.Viewport.StateHide

type NavigationMenuViewportState = {}

Arrow

Displays an element pointing toward the navigation menu’s current anchor. Renders a <div> element.

classNamestring | function—

Name: className
Description: CSS class applied to the element, or a function that returns a class based on the component’s state.
Type: | string | (( state: NavigationMenu.Arrow.State, ) => string | undefined) | undefined

styleReact.CSSProperties | function—

Name: style
Type: | React.CSSProperties | (( state: NavigationMenu.Arrow.State, ) => React.CSSProperties | undefined) | undefined

renderReactElement | function—

Name: render
Description: Allows you to replace the component’s HTML element with a different tag, or compose it with another component.

Accepts a ReactElement or a function that returns the element to render.
Type: | ReactElement | (( props: HTMLProps, state: NavigationMenu.Arrow.State, ) => ReactElement) | undefined

data-open

Present when the popup is open.

data-closed

Present when the popup is closed.

data-uncentered

Present when the popup arrow is uncentered.

data-align

Indicates how the popup is aligned relative to specified side.

data-side

Indicates which side the popup is positioned relative to the trigger.

Attribute	Description	-
`data-open`	Present when the popup is open.
`data-closed`	Present when the popup is closed.
`data-uncentered`	Present when the popup arrow is uncentered.
`data-align`	Indicates how the popup is aligned relative to specified side.
`data-side`	Indicates which side the popup is positioned relative to the trigger.

NavigationMenu.Arrow.PropsHide

Re-Export of Arrow props as NavigationMenuArrowProps

NavigationMenu.Arrow.StateHide

type NavigationMenuArrowState = {
  /** Whether the popup is currently open. */
  open: boolean;
  /** The side of the anchor the component is placed on. */
  side: 'top' | 'bottom' | 'left' | 'right' | 'inline-end' | 'inline-start';
  /** The alignment of the component relative to the anchor. */
  align: 'start' | 'center' | 'end';
  /** Whether the arrow cannot be centered on the anchor. */
  uncentered: boolean;
}

Navigation Menu

NavigationMenu.Root.PropsHide

NavigationMenu.Root.StateHide

NavigationMenu.Root.ActionsHide

NavigationMenu.Root.ChangeEventReasonHide

NavigationMenu.Root.ChangeEventDetailsHide

NavigationMenu.Root.ValueHide

NavigationMenu.List.PropsHide

NavigationMenu.List.StateHide

NavigationMenu.Item.PropsHide

NavigationMenu.Item.StateHide

NavigationMenu.Trigger.PropsHide

NavigationMenu.Trigger.StateHide

NavigationMenu.Icon.PropsHide

NavigationMenu.Icon.StateHide

NavigationMenu.Content.PropsHide

NavigationMenu.Content.StateHide

NavigationMenu.Link.PropsHide

NavigationMenu.Link.StateHide

NavigationMenu.Backdrop.PropsHide

NavigationMenu.Backdrop.StateHide

NavigationMenu.Portal.PropsHide

NavigationMenu.Portal.StateHide

NavigationMenu.Positioner.PropsHide

NavigationMenu.Positioner.StateHide

NavigationMenu.Popup.PropsHide

NavigationMenu.Popup.StateHide

NavigationMenu.Viewport.PropsHide

NavigationMenu.Viewport.StateHide

NavigationMenu.Arrow.PropsHide

NavigationMenu.Arrow.StateHide