Files
blockly/core/interfaces/i_navigation_policy.ts

61 lines
2.0 KiB
TypeScript

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