blockly/core/keyboard_nav/marker.ts

/**
 * @license
 * Copyright 2019 Google LLC
 * SPDX-License-Identifier: Apache-2.0
 */

/**
 * The class representing a marker.
 * Used primarily for keyboard navigation to show a marked location.
 *
 * @class
 */
// Former goog.module ID: Blockly.Marker

import {BlockSvg} from '../block_svg.js';
import {Field} from '../field.js';
import type {IFocusableNode} from '../interfaces/i_focusable_node.js';
import {RenderedConnection} from '../rendered_connection.js';

/**
 * Class for a marker.
 * This is used in keyboard navigation to save a location in the Blockly AST.
 */
export class Marker {
  /** The colour of the marker. */
  colour: string | null = null;

  /** The current location of the marker. */
  protected curNode: IFocusableNode | null = null;

  /** The type of the marker. */
  type = 'marker';

  /**
   * Gets the current location of the marker.
   *
   * @returns The current field, connection, or block the marker is on.
   */
  getCurNode(): IFocusableNode | null {
    return this.curNode;
  }

  /**
   * Set the location of the marker and call the update method.
   *
   * @param newNode The new location of the marker, or null to remove it.
   */
  setCurNode(newNode: IFocusableNode | null) {
    this.curNode = newNode;
  }

  /** Dispose of this marker. */
  dispose() {
    this.curNode = null;
  }

  /**
   * Returns the block that the given node is a child of.
   *
   * @returns The parent block of the node if any, otherwise null.
   */
  getSourceBlockFromNode(node: IFocusableNode | null): BlockSvg | null {
    if (node instanceof BlockSvg) {
      return node;
    } else if (node instanceof Field) {
      return node.getSourceBlock() as BlockSvg;
    } else if (node instanceof RenderedConnection) {
      return node.getSourceBlock();
    }

    return null;
  }

  /**
   * Returns the block that this marker's current node is a child of.
   *
   * @returns The parent block of the marker's current node if any, otherwise
   *     null.
   */
  getSourceBlock(): BlockSvg | null {
    return this.getSourceBlockFromNode(this.getCurNode());
  }
}