feat: Add a VarTypeChange event. (#8402)

* feat: Add a VarTypeChange event.

* chore: Update copyright date.

* refactor: Inline fields in the constructor.

core/events/events.ts

@@ -43,6 +43,7 @@ import {VarBase, VarBaseJson} from './events_var_base.js';
 import {VarCreate, VarCreateJson} from './events_var_create.js';
 import {VarDelete, VarDeleteJson} from './events_var_delete.js';
 import {VarRename, VarRenameJson} from './events_var_rename.js';
+import {VarTypeChange, VarTypeChangeJson} from './events_var_type_change.js';
 import {ViewportChange, ViewportChangeJson} from './events_viewport.js';
 import * as eventUtils from './utils.js';
 import {FinishedLoading} from './workspace_events.js';
@@ -105,6 +106,8 @@ export {VarDelete};
 export {VarDeleteJson};
 export {VarRename};
 export {VarRenameJson};
+export {VarTypeChange};
+export {VarTypeChangeJson};
 export {ViewportChange};
 export {ViewportChangeJson};
 
@@ -140,6 +143,7 @@ export const UI = eventUtils.UI;
 export const VAR_CREATE = eventUtils.VAR_CREATE;
 export const VAR_DELETE = eventUtils.VAR_DELETE;
 export const VAR_RENAME = eventUtils.VAR_RENAME;
+export const VAR_TYPE_CHAGE = eventUtils.VAR_TYPE_CHANGE;
 export const VIEWPORT_CHANGE = eventUtils.VIEWPORT_CHANGE;
 
 // Event utils.

core/events/events_var_type_change.ts

@@ -0,0 +1,122 @@
+/**
+ * @license
+ * Copyright 2024 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/**
+ * Class for a variable type change event.
+ *
+ * @class
+ */
+
+import * as registry from '../registry.js';
+import type {
+  IVariableModel,
+  IVariableState,
+} from '../interfaces/i_variable_model.js';
+
+import {VarBase, VarBaseJson} from './events_var_base.js';
+import * as eventUtils from './utils.js';
+import type {Workspace} from '../workspace.js';
+
+/**
+ * Notifies listeners that a variable's type has changed.
+ */
+export class VarTypeChange extends VarBase {
+  override type = eventUtils.VAR_TYPE_CHANGE;
+
+  /**
+   * @param variable The variable whose type changed. Undefined for a blank event.
+   * @param oldType The old type of the variable. Undefined for a blank event.
+   * @param newType The new type of the variable. Undefined for a blank event.
+   */
+  constructor(
+    variable?: IVariableModel<IVariableState>,
+    public oldType?: string,
+    public newType?: string,
+  ) {
+    super(variable);
+  }
+
+  /**
+   * Encode the event as JSON.
+   *
+   * @returns JSON representation.
+   */
+  override toJson(): VarTypeChangeJson {
+    const json = super.toJson() as VarTypeChangeJson;
+    if (!this.oldType || !this.newType) {
+      throw new Error(
+        "The variable's types are undefined. Either pass them to " +
+          'the constructor, or call fromJson',
+      );
+    }
+    json['oldType'] = this.oldType;
+    json['newType'] = this.newType;
+    return json;
+  }
+
+  /**
+   * Deserializes the JSON event.
+   *
+   * @param event The event to append new properties to. Should be a subclass
+   *     of VarTypeChange, but we can't specify that due to the fact that
+   *     parameters to static methods in subclasses must be supertypes of
+   *     parameters to static methods in superclasses.
+   * @internal
+   */
+  static fromJson(
+    json: VarTypeChangeJson,
+    workspace: Workspace,
+    event?: any,
+  ): VarTypeChange {
+    const newEvent = super.fromJson(
+      json,
+      workspace,
+      event ?? new VarTypeChange(),
+    ) as VarTypeChange;
+    newEvent.oldType = json['oldType'];
+    newEvent.newType = json['newType'];
+    return newEvent;
+  }
+
+  /**
+   * Run a variable type change event.
+   *
+   * @param forward True if run forward, false if run backward (undo).
+   */
+  override run(forward: boolean) {
+    const workspace = this.getEventWorkspace_();
+    if (!this.varId) {
+      throw new Error(
+        'The var ID is undefined. Either pass a variable to ' +
+          'the constructor, or call fromJson',
+      );
+    }
+    if (!this.oldType || !this.newType) {
+      throw new Error(
+        "The variable's types are undefined. Either pass them to " +
+          'the constructor, or call fromJson',
+      );
+    }
+    const variable = workspace.getVariableMap().getVariableById(this.varId);
+    if (!variable) return;
+    if (forward) {
+      workspace.getVariableMap().changeVariableType(variable, this.newType);
+    } else {
+      workspace.getVariableMap().changeVariableType(variable, this.oldType);
+    }
+  }
+}
+
+export interface VarTypeChangeJson extends VarBaseJson {
+  oldType: string;
+  newType: string;
+}
+
+registry.register(
+  registry.Type.EVENT,
+  eventUtils.VAR_TYPE_CHANGE,
+  VarTypeChange,
+);

core/events/utils.ts

@@ -111,6 +111,11 @@ export const VAR_DELETE = 'var_delete';
  */
 export const VAR_RENAME = 'var_rename';
 
+/**
+ * Name of event that changes a variable's type.
+ */
+export const VAR_TYPE_CHANGE = 'var_type_change';
+
 /**
  * Name of generic event that records a UI change.
  */

tests/mocha/event_var_type_change_test.js

@@ -0,0 +1,43 @@
+/**
+ * @license
+ * Copyright 2024 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import {assert} from '../../node_modules/chai/chai.js';
+import {
+  sharedTestSetup,
+  sharedTestTeardown,
+} from './test_helpers/setup_teardown.js';
+
+suite('Var Type Change Event', function () {
+  setup(function () {
+    sharedTestSetup.call(this);
+    this.workspace = new Blockly.Workspace();
+  });
+
+  teardown(function () {
+    sharedTestTeardown.call(this);
+  });
+
+  suite('Serialization', function () {
+    test('variable type change events round-trip through JSON', function () {
+      const varModel = new Blockly.VariableModel(
+        this.workspace,
+        'name',
+        'foo',
+        'id',
+      );
+      const origEvent = new Blockly.Events.VarTypeChange(
+        varModel,
+        'foo',
+        'bar',
+      );
+
+      const json = origEvent.toJson();
+      const newEvent = new Blockly.Events.fromJson(json, this.workspace);
+
+      assert.deepEqual(newEvent, origEvent);
+    });
+  });
+});

tests/mocha/index.html

@@ -76,6 +76,7 @@
       import './event_var_create_test.js';
       import './event_var_delete_test.js';
       import './event_var_rename_test.js';
+      import './event_var_type_change_test.js';
       import './event_viewport_test.js';
       import './extensions_test.js';
       import './field_checkbox_test.js';