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ae22165cbe
* refactor: Remove INavigable in favor of IFocusableNode. * chore: Fix JSDoc. * chore: Address review feedback.
70 lines
2.3 KiB
TypeScript
70 lines
2.3 KiB
TypeScript
/**
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* @license
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* Copyright 2025 Google LLC
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* SPDX-License-Identifier: Apache-2.0
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*/
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import type {IFocusableNode} from './i_focusable_node.js';
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/**
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* A set of rules that specify where keyboard navigation should proceed.
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*/
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export interface INavigationPolicy<T> {
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/**
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* Returns the first child element of the given element, if any.
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*
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* @param current The element which the user is navigating into.
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* @returns The current element's first child, or null if it has none.
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*/
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getFirstChild(current: T): IFocusableNode | null;
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/**
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* Returns the parent element of the given element, if any.
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*
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* @param current The element which the user is navigating out of.
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* @returns The parent element of the current element, or null if it has none.
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*/
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getParent(current: T): IFocusableNode | null;
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/**
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* Returns the peer element following the given element, if any.
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*
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* @param current The element which the user is navigating past.
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* @returns The next peer element of the current element, or null if there is
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* none.
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*/
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getNextSibling(current: T): IFocusableNode | null;
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/**
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* Returns the peer element preceding the given element, if any.
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*
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* @param current The element which the user is navigating past.
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* @returns The previous peer element of the current element, or null if
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* there is none.
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*/
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getPreviousSibling(current: T): IFocusableNode | null;
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/**
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* Returns whether or not the given instance should be reachable via keyboard
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* navigation.
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*
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* Implementors should generally return true, unless there are circumstances
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* under which this item should be skipped while using keyboard navigation.
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* Common examples might include being disabled, invalid, readonly, or purely
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* a visual decoration. For example, while Fields are navigable, non-editable
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* fields return false, since they cannot be interacted with when focused.
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*
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* @returns True if this element should be included in keyboard navigation.
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*/
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isNavigable(current: T): boolean;
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/**
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* Returns whether or not this navigation policy corresponds to the type of
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* the given object.
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*
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* @param current An instance to check whether this policy applies to.
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* @returns True if the given object is of a type handled by this policy.
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*/
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isApplicable(current: any): current is T;
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}
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