Files
blockly/core/delete_area.ts
2022-08-01 13:09:51 -07:00

95 lines
2.6 KiB
TypeScript

/**
* @license
* Copyright 2021 Google LLC
* SPDX-License-Identifier: Apache-2.0
*/
/**
* @fileoverview The abstract class for a component that can delete a block or
* bubble that is dropped on top of it.
*/
'use strict';
/**
* The abstract class for a component that can delete a block or
* bubble that is dropped on top of it.
* @class
*/
goog.module('Blockly.DeleteArea');
const {BlockSvg} = goog.require('Blockly.BlockSvg');
const {DragTarget} = goog.require('Blockly.DragTarget');
/* eslint-disable-next-line no-unused-vars */
const {IDeleteArea} = goog.require('Blockly.IDeleteArea');
/* eslint-disable-next-line no-unused-vars */
const {IDraggable} = goog.requireType('Blockly.IDraggable');
/**
* Abstract class for a component that can delete a block or bubble that is
* dropped on top of it.
* @extends {DragTarget}
* @implements {IDeleteArea}
* @alias Blockly.DeleteArea
*/
class DeleteArea extends DragTarget {
/**
* Constructor for DeleteArea. Should not be called directly, only by a
* subclass.
*/
constructor() {
super();
/**
* Whether the last block or bubble dragged over this delete area would be
* deleted if dropped on this component.
* This property is not updated after the block or bubble is deleted.
* @type {boolean}
* @protected
*/
this.wouldDelete_ = false;
/**
* The unique id for this component that is used to register with the
* ComponentManager.
* @type {string}
*/
this.id;
}
/**
* Returns whether the provided block or bubble would be deleted if dropped on
* this area.
* This method should check if the element is deletable and is always called
* before onDragEnter/onDragOver/onDragExit.
* @param {!IDraggable} element The block or bubble currently being
* dragged.
* @param {boolean} couldConnect Whether the element could could connect to
* another.
* @return {boolean} Whether the element provided would be deleted if dropped
* on this area.
*/
wouldDelete(element, couldConnect) {
if (element instanceof BlockSvg) {
const block = /** @type {BlockSvg} */ (element);
const couldDeleteBlock = !block.getParent() && block.isDeletable();
this.updateWouldDelete_(couldDeleteBlock && !couldConnect);
} else {
this.updateWouldDelete_(element.isDeletable());
}
return this.wouldDelete_;
}
/**
* Updates the internal wouldDelete_ state.
* @param {boolean} wouldDelete The new value for the wouldDelete state.
* @protected
*/
updateWouldDelete_(wouldDelete) {
this.wouldDelete_ = wouldDelete;
}
}
exports.DeleteArea = DeleteArea;