Bootstrap

API navManager

createNavManager

function

createNavManager<T>(): NavManager<T>

Returns a new instance of the navigation manager.

The navigation manager simplifies keyboard navigation for a set of DOM elements. It provides a directive to use on some DOM elements, both to add the keydown event handler and to specify which elements should be managed (either by directly putting the directive on those elements, or by putting the directive on a parent element and specifying which child elements should be included through a selector function).

It provides some utilities to move the focus between those elements (focusFirst/focusLast, focusLeft/focusRight, focusPrevious/focusNext).

Type Parameters

T

The type of the context object used in the navigation manager.

Returns

NavManager<T>

An object containing methods and properties for managing focus navigation.


FocusEnd

type alias

FocusEnd: (arg?) => HTMLElement | null

A type representing a function that focuses on the end element.

Parameters

arg?

arg.event?: Event

Returns

HTMLElement | null

The HTMLElement that was focused, or null if no element was focused.


FocusNeighbour

type alias

FocusNeighbour: (arg?) => HTMLElement | null

A type representing a function that determines the neighboring element to focus on.

Parameters

arg?

arg.event?: Event

arg.referenceElement?: HTMLElement | null

Returns

HTMLElement | null

The next HTMLElement to focus on, or null if no suitable element is found.


getKeyName

function

getKeyName(event): string

Returns the key name given the keyboard event. The key name is built using event.key (such as ArrowLeft, PageDown...), prefixed with the modifiers. If present, modifiers are always in the same order: Meta+Ctrl+Alt+Shift+...

Parameters

event: KeyboardEvent

keyboard event

Returns

string

the name of the key, including modifiers


isInternalInputNavigation

function

isInternalInputNavigation(event): boolean

Returns true if the keyboard event is an ArrowLeft, ArrowRight, Home or End key press that should make the cursor move inside the input and false otherwise (i.e. the key is not ArrowLeft, ArrowRight, Home or End key, or that would not make the cursor move because it is already at one end of the input)

Parameters

event: KeyboardEvent

keyboard event

Returns

boolean

true if the keyboard event is an ArrowLeft, ArrowRight, Home or End key press that should make the cursor move inside the input and false otherwise.


type alias

NavManager<T>: object

Represents a navigation manager that handles focusable elements in the DOM.

Type Parameters

T

The type of the configuration for the navigation manager items.

Type declaration

directive: Directive<NavManagerItemConfig<T>, SSRHTMLElement>

Directive to attach the nav manager

elementsInDomOrder$: ReadableSignal<HTMLElement[]>

Store containing the navigable elements in DOM order

focusFirst: FocusEnd

Focus the first element, respecting the anscestor direction.

focusFirstLeft: FocusEnd

Focus the element at the left-end of the list.

focusFirstRight: FocusEnd

Focus the element at the right-end of the list.

focusIndex: (index, moveDirection) => HTMLElement | null

Focus the element at the given idex. If the element at the given index is not focusable, use the moveDirection to step into the next focusable element.

Parameters

index: number

the index of the element to focus

moveDirection: -1 | 0 | 1

a move direction

Returns

HTMLElement | null

the new focusable element if found, null otherwise

focusLast: FocusEnd

Focus the last element, respecting the anscestor direction.

focusLeft: FocusNeighbour

Focus the next focusable element to the left of the currently focused element.

focusNext: FocusNeighbour

Focus the next element, respecting the anscestor direction.

focusPrevious: FocusNeighbour

Focus the previous element, respecting the anscestor direction.

focusRight: FocusNeighbour

Focus the next focusable element to the right of the currently focused element.

refreshElements: (now?) => void

Refresh the elements list.

Parameters

now?: boolean

force the instant refresh of the elements

Returns

void


interface

Configuration object for a navigation manager item.

Type Parameters

T = any

The type of the context object.

Properties

optional context: T


optional keys: Record<string, NavManagerKeyHandler<T>>

Map of key handlers. The key in the map should match the result of calling getKeyName on the key event (for example "ArrowLeft" or "Ctrl+PageDown"). The value in the map is the corresponding key handler.


optional selector: (directiveElement) => Iterable<HTMLElement>

Function returning DOM elements to include in the navigation manager. It receives as a parameter the DOM element on which the navigation manager directive is used. If not specified, the default selector function only returns the element on which the navigation manager directive is used.

Parameters

directiveElement: HTMLElement

Returns

Iterable<HTMLElement>


type alias

NavManagerKeyHandler<T>: (info) => void

Type of a key handler of the navigation manager. A key handler receives an object as its parameter, with the following properties:

  • event: key event
  • directiveElement: DOM element which has the navigation manager directive
  • navManager: navigation manager instance
Type Parameters

T = any

The type of the context object, defaults to any.

Parameters

info

info.context?: T

info.directiveElement: HTMLElement

info.event: Event

info.navManager: NavManager<T>

Returns

void