refactor(events): introduce EventType enum in separate module (#8530)

* refactor(events): Use "export ... from" where applicable

* refactor(events): Introduce EventType enum

  Introduce an enum for the event .type values.  We can't actually
  use it as the type of the .type property on Abstract events,
  because we want to allow developers to add their own custom
  event types inheriting from this type, but at least this way we
  can be reasonably sure that all of our own event subclasses have
  distinct .type values—plus consistent use of enum syntax
  (EventType.TYPE_NAME) is probably good for readability overall.

  Put it in a separate module from the rest of events/utils.ts
  because it would be helpful if event utils could use

      event instanceof SomeEventType

  for type narrowing but but at the moment most events are in
  modules that depend on events/utils.ts for their .type
  constant, and although circular ESM dependencies should work
  in principle there are various restrictions and this
  particular circularity causes issues at the moment.

  A few of the event classes also depend on utils.ts for fire()
  or other functions, which will be harder to deal with, but at
  least this commit is win in terms of reducing the complexity
  of our dependencies, making most of the Abstract event subclass
  module dependent on type.ts, which has no imports, rather than
  on utils.ts which has multiple imports.

core/block.ts

@@ -26,6 +26,7 @@ import * as constants from './constants.js';
 import type {Abstract} from './events/events_abstract.js';
 import type {BlockChange} from './events/events_block_change.js';
 import type {BlockMove} from './events/events_block_move.js';
+import {EventType} from './events/type.js';
 import * as eventUtils from './events/utils.js';
 import * as Extensions from './extensions.js';
 import type {Field} from './field.js';
@@ -304,7 +305,7 @@ export class Block implements IASTNodeLocation {
 
       // Fire a create event.
       if (eventUtils.isEnabled()) {
-        eventUtils.fire(new (eventUtils.get(eventUtils.BLOCK_CREATE))(this));
+        eventUtils.fire(new (eventUtils.get(EventType.BLOCK_CREATE))(this));
       }
     } finally {
       eventUtils.setGroup(existingGroup);
@@ -339,7 +340,7 @@ export class Block implements IASTNodeLocation {
     this.unplug(healStack);
     if (eventUtils.isEnabled()) {
       // Constructing the delete event is costly. Only perform if necessary.
-      eventUtils.fire(new (eventUtils.get(eventUtils.BLOCK_DELETE))(this));
+      eventUtils.fire(new (eventUtils.get(EventType.BLOCK_DELETE))(this));
     }
     this.workspace.removeTopBlock(this);
     this.disposeInternal();
@@ -1329,7 +1330,7 @@ export class Block implements IASTNodeLocation {
   setInputsInline(newBoolean: boolean) {
     if (this.inputsInline !== newBoolean) {
       eventUtils.fire(
-        new (eventUtils.get(eventUtils.BLOCK_CHANGE))(
+        new (eventUtils.get(EventType.BLOCK_CHANGE))(
           this,
           'inline',
           null,
@@ -1491,7 +1492,7 @@ export class Block implements IASTNodeLocation {
       } else {
         this.disabledReasons.delete(reason);
       }
-      const blockChangeEvent = new (eventUtils.get(eventUtils.BLOCK_CHANGE))(
+      const blockChangeEvent = new (eventUtils.get(EventType.BLOCK_CHANGE))(
         this,
         'disabled',
         /* name= */ null,
@@ -1559,7 +1560,7 @@ export class Block implements IASTNodeLocation {
   setCollapsed(collapsed: boolean) {
     if (this.collapsed_ !== collapsed) {
       eventUtils.fire(
-        new (eventUtils.get(eventUtils.BLOCK_CHANGE))(
+        new (eventUtils.get(EventType.BLOCK_CHANGE))(
           this,
           'collapsed',
           null,
@@ -2358,7 +2359,7 @@ export class Block implements IASTNodeLocation {
     }
 
     eventUtils.fire(
-      new (eventUtils.get(eventUtils.BLOCK_CHANGE))(
+      new (eventUtils.get(EventType.BLOCK_CHANGE))(
         this,
         'comment',
         null,
@@ -2458,12 +2459,8 @@ export class Block implements IASTNodeLocation {
     if (this.parentBlock_) {
       throw Error('Block has parent');
     }
-    const event = new (eventUtils.get(eventUtils.BLOCK_MOVE))(
-      this,
-    ) as BlockMove;
-    if (reason) {
-      event.setReason(reason);
-    }
+    const event = new (eventUtils.get(EventType.BLOCK_MOVE))(this) as BlockMove;
+    if (reason) event.setReason(reason);
     this.xy_.translate(dx, dy);
     event.recordNew();
     eventUtils.fire(event);

core/block_svg.ts

@@ -32,6 +32,7 @@ import {
 } from './contextmenu_registry.js';
 import {BlockDragStrategy} from './dragging/block_drag_strategy.js';
 import type {BlockMove} from './events/events_block_move.js';
+import {EventType} from './events/type.js';
 import * as eventUtils from './events/utils.js';
 import type {Field} from './field.js';
 import {FieldLabel} from './field_label.js';
@@ -377,10 +378,8 @@ export class BlockSvg
     const eventsEnabled = eventUtils.isEnabled();
     let event: BlockMove | null = null;
     if (eventsEnabled) {
-      event = new (eventUtils.get(eventUtils.BLOCK_MOVE)!)(this) as BlockMove;
-      if (reason) {
-        event.setReason(reason);
-      }
+      event = new (eventUtils.get(EventType.BLOCK_MOVE)!)(this) as BlockMove;
+      if (reason) event.setReason(reason);
     }
 
     const delta = new Coordinate(dx, dy);

core/bump_objects.ts

@@ -14,6 +14,7 @@ import type {CommentCreate} from './events/events_comment_create.js';
 import type {CommentMove} from './events/events_comment_move.js';
 import type {CommentResize} from './events/events_comment_resize.js';
 import type {ViewportChange} from './events/events_viewport.js';
+import {BUMP_EVENTS, EventType} from './events/type.js';
 import * as eventUtils from './events/utils.js';
 import type {IBoundedElement} from './interfaces/i_bounded_element.js';
 import type {ContainerRegion} from './metrics_manager.js';
@@ -99,7 +100,7 @@ export function bumpIntoBoundsHandler(
       return;
     }
 
-    if (eventUtils.BUMP_EVENTS.includes(e.type ?? '')) {
+    if (BUMP_EVENTS.includes(e.type ?? '')) {
       const scrollMetricsInWsCoords = metricsManager.getScrollMetrics(true);
 
       // Triggered by move/create event
@@ -127,7 +128,7 @@ export function bumpIntoBoundsHandler(
         );
       }
       eventUtils.setGroup(existingGroup);
-    } else if (e.type === eventUtils.VIEWPORT_CHANGE) {
+    } else if (e.type === EventType.VIEWPORT_CHANGE) {
       const viewportEvent = e as ViewportChange;
       if (
         viewportEvent.scale &&
@@ -155,16 +156,16 @@ function extractObjectFromEvent(
 ): IBoundedElement | null {
   let object = null;
   switch (e.type) {
-    case eventUtils.BLOCK_CREATE:
-    case eventUtils.BLOCK_MOVE:
+    case EventType.BLOCK_CREATE:
+    case EventType.BLOCK_MOVE:
       object = workspace.getBlockById((e as BlockCreate | BlockMove).blockId!);
       if (object) {
         object = object.getRootBlock();
       }
       break;
-    case eventUtils.COMMENT_CREATE:
-    case eventUtils.COMMENT_MOVE:
-    case eventUtils.COMMENT_RESIZE:
+    case EventType.COMMENT_CREATE:
+    case EventType.COMMENT_MOVE:
+    case EventType.COMMENT_RESIZE:
       object = workspace.getCommentById(
         (e as CommentCreate | CommentMove | CommentResize).commentId!,
       ) as RenderedWorkspaceComment;

core/clipboard/block_paster.ts

@@ -7,6 +7,7 @@
 import {BlockSvg} from '../block_svg.js';
 import * as common from '../common.js';
 import {config} from '../config.js';
+import {EventType} from '../events/type.js';
 import * as eventUtils from '../events/utils.js';
 import {ICopyData} from '../interfaces/i_copyable.js';
 import {IPaster} from '../interfaces/i_paster.js';
@@ -52,7 +53,7 @@ export class BlockPaster implements IPaster<BlockCopyData, BlockSvg> {
     if (!block) return block;
 
     if (eventUtils.isEnabled() && !block.isShadow()) {
-      eventUtils.fire(new (eventUtils.get(eventUtils.BLOCK_CREATE))(block));
+      eventUtils.fire(new (eventUtils.get(EventType.BLOCK_CREATE))(block));
     }
     common.setSelected(block);
     return block;

core/clipboard/workspace_comment_paster.ts

@@ -6,6 +6,7 @@
 
 import {RenderedWorkspaceComment} from '../comments/rendered_workspace_comment.js';
 import * as common from '../common.js';
+import {EventType} from '../events/type.js';
 import * as eventUtils from '../events/utils.js';
 import {ICopyData} from '../interfaces/i_copyable.js';
 import {IPaster} from '../interfaces/i_paster.js';
@@ -46,7 +47,7 @@ export class WorkspaceCommentPaster
     if (!comment) return null;
 
     if (eventUtils.isEnabled()) {
-      eventUtils.fire(new (eventUtils.get(eventUtils.COMMENT_CREATE))(comment));
+      eventUtils.fire(new (eventUtils.get(EventType.COMMENT_CREATE))(comment));
     }
     common.setSelected(comment);
     return comment;

core/comments/workspace_comment.ts

@@ -6,6 +6,7 @@
 
 import {CommentMove} from '../events/events_comment_move.js';
 import {CommentResize} from '../events/events_comment_resize.js';
+import {EventType} from '../events/type.js';
 import * as eventUtils from '../events/utils.js';
 import {Coordinate} from '../utils/coordinate.js';
 import * as idGenerator from '../utils/idgenerator.js';
@@ -63,21 +64,21 @@ export class WorkspaceComment {
 
   private fireCreateEvent() {
     if (eventUtils.isEnabled()) {
-      eventUtils.fire(new (eventUtils.get(eventUtils.COMMENT_CREATE))(this));
+      eventUtils.fire(new (eventUtils.get(EventType.COMMENT_CREATE))(this));
     }
   }
 
   private fireDeleteEvent() {
     if (eventUtils.isEnabled()) {
-      eventUtils.fire(new (eventUtils.get(eventUtils.COMMENT_DELETE))(this));
+      eventUtils.fire(new (eventUtils.get(EventType.COMMENT_DELETE))(this));
     }
   }
 
   /** Fires a comment change event. */
   private fireChangeEvent(oldText: string, newText: string) {
     if (eventUtils.isEnabled()) {
       eventUtils.fire(
-        new (eventUtils.get(eventUtils.COMMENT_CHANGE))(this, oldText, newText),
+        new (eventUtils.get(EventType.COMMENT_CHANGE))(this, oldText, newText),
       );
     }
   }
@@ -86,7 +87,7 @@ export class WorkspaceComment {
   private fireCollapseEvent(newCollapsed: boolean) {
     if (eventUtils.isEnabled()) {
       eventUtils.fire(
-        new (eventUtils.get(eventUtils.COMMENT_COLLAPSE))(this, newCollapsed),
+        new (eventUtils.get(EventType.COMMENT_COLLAPSE))(this, newCollapsed),
       );
     }
   }
@@ -105,7 +106,7 @@ export class WorkspaceComment {
 
   /** Sets the comment's size in workspace units. */
   setSize(size: Size) {
-    const event = new (eventUtils.get(eventUtils.COMMENT_RESIZE))(
+    const event = new (eventUtils.get(EventType.COMMENT_RESIZE))(
       this,
     ) as CommentResize;
 
@@ -196,7 +197,7 @@ export class WorkspaceComment {
 
   /** Moves the comment to the given location in workspace coordinates. */
   moveTo(location: Coordinate, reason?: string[] | undefined) {
-    const event = new (eventUtils.get(eventUtils.COMMENT_MOVE))(
+    const event = new (eventUtils.get(EventType.COMMENT_MOVE))(
       this,
     ) as CommentMove;
     if (reason) event.setReason(reason);

core/common.ts

@@ -10,6 +10,7 @@ import type {Block} from './block.js';
 import {ISelectable} from './blockly.js';
 import {BlockDefinition, Blocks} from './blocks.js';
 import type {Connection} from './connection.js';
+import {EventType} from './events/type.js';
 import * as eventUtils from './events/utils.js';
 import type {Workspace} from './workspace.js';
 import type {WorkspaceSvg} from './workspace_svg.js';
@@ -107,7 +108,7 @@ export function getSelected(): ISelectable | null {
 export function setSelected(newSelection: ISelectable | null) {
   if (selected === newSelection) return;
 
-  const event = new (eventUtils.get(eventUtils.SELECTED))(
+  const event = new (eventUtils.get(EventType.SELECTED))(
     selected?.id ?? null,
     newSelection?.id ?? null,
     newSelection?.workspace.id ?? selected?.workspace.id ?? '',

core/connection.ts

@@ -14,6 +14,7 @@
 import type {Block} from './block.js';
 import {ConnectionType} from './connection_type.js';
 import type {BlockMove} from './events/events_block_move.js';
+import {EventType} from './events/type.js';
 import * as eventUtils from './events/utils.js';
 import type {Input} from './inputs/input.js';
 import type {IASTNodeLocationWithBlock} from './interfaces/i_ast_node_location_with_block.js';
@@ -114,7 +115,7 @@ export class Connection implements IASTNodeLocationWithBlock {
     // Connect the new connection to the parent.
     let event;
     if (eventUtils.isEnabled()) {
-      event = new (eventUtils.get(eventUtils.BLOCK_MOVE))(
+      event = new (eventUtils.get(EventType.BLOCK_MOVE))(
         childBlock,
       ) as BlockMove;
       event.setReason(['connect']);
@@ -281,7 +282,7 @@ export class Connection implements IASTNodeLocationWithBlock {
 
     let event;
     if (eventUtils.isEnabled()) {
-      event = new (eventUtils.get(eventUtils.BLOCK_MOVE))(
+      event = new (eventUtils.get(EventType.BLOCK_MOVE))(
         childConnection.getSourceBlock(),
       ) as BlockMove;
       event.setReason(['disconnect']);

core/contextmenu.ts

@@ -15,6 +15,7 @@ import type {
   ContextMenuOption,
   LegacyContextMenuOption,
 } from './contextmenu_registry.js';
+import {EventType} from './events/type.js';
 import * as eventUtils from './events/utils.js';
 import {Menu} from './menu.js';
 import {MenuItem} from './menuitem.js';
@@ -260,7 +261,7 @@ export function callbackFactory(
       eventUtils.enable();
     }
     if (eventUtils.isEnabled() && !newBlock.isShadow()) {
-      eventUtils.fire(new (eventUtils.get(eventUtils.BLOCK_CREATE))(newBlock));
+      eventUtils.fire(new (eventUtils.get(EventType.BLOCK_CREATE))(newBlock));
     }
     common.setSelected(newBlock);
     return newBlock;

core/dragging/block_drag_strategy.ts

@@ -12,6 +12,7 @@ import {config} from '../config.js';
 import {Connection} from '../connection.js';
 import {ConnectionType} from '../connection_type.js';
 import type {BlockMove} from '../events/events_block_move.js';
+import {EventType} from '../events/type.js';
 import * as eventUtils from '../events/utils.js';
 import {IConnectionPreviewer} from '../interfaces/i_connection_previewer.js';
 import {IDragStrategy} from '../interfaces/i_draggable.js';
@@ -177,7 +178,7 @@ export class BlockDragStrategy implements IDragStrategy {
 
   /** Fire a UI event at the start of a block drag. */
   private fireDragStartEvent() {
-    const event = new (eventUtils.get(eventUtils.BLOCK_DRAG))(
+    const event = new (eventUtils.get(EventType.BLOCK_DRAG))(
       this.block,
       true,
       this.block.getDescendants(false),
@@ -187,7 +188,7 @@ export class BlockDragStrategy implements IDragStrategy {
 
   /** Fire a UI event at the end of a block drag. */
   private fireDragEndEvent() {
-    const event = new (eventUtils.get(eventUtils.BLOCK_DRAG))(
+    const event = new (eventUtils.get(EventType.BLOCK_DRAG))(
       this.block,
       false,
       this.block.getDescendants(false),
@@ -198,7 +199,7 @@ export class BlockDragStrategy implements IDragStrategy {
   /** Fire a move event at the end of a block drag. */
   private fireMoveEvent() {
     if (this.block.isDeadOrDying()) return;
-    const event = new (eventUtils.get(eventUtils.BLOCK_MOVE))(
+    const event = new (eventUtils.get(EventType.BLOCK_MOVE))(
       this.block,
     ) as BlockMove;
     event.setReason(['drag']);

core/dragging/comment_drag_strategy.ts

@@ -6,6 +6,7 @@
 
 import {RenderedWorkspaceComment} from '../comments.js';
 import {CommentMove} from '../events/events_comment_move.js';
+import {EventType} from '../events/type.js';
 import * as eventUtils from '../events/utils.js';
 import {IDragStrategy} from '../interfaces/i_draggable.js';
 import * as layers from '../layers.js';
@@ -63,7 +64,7 @@ export class CommentDragStrategy implements IDragStrategy {
 
   /** Fire a UI event at the start of a comment drag. */
   private fireDragStartEvent() {
-    const event = new (eventUtils.get(eventUtils.COMMENT_DRAG))(
+    const event = new (eventUtils.get(EventType.COMMENT_DRAG))(
       this.comment,
       true,
     );
@@ -72,7 +73,7 @@ export class CommentDragStrategy implements IDragStrategy {
 
   /** Fire a UI event at the end of a comment drag. */
   private fireDragEndEvent() {
-    const event = new (eventUtils.get(eventUtils.COMMENT_DRAG))(
+    const event = new (eventUtils.get(EventType.COMMENT_DRAG))(
       this.comment,
       false,
     );
@@ -82,7 +83,7 @@ export class CommentDragStrategy implements IDragStrategy {
   /** Fire a move event at the end of a comment drag. */
   private fireMoveEvent() {
     if (this.comment.isDeadOrDying()) return;
-    const event = new (eventUtils.get(eventUtils.COMMENT_MOVE))(
+    const event = new (eventUtils.get(EventType.COMMENT_MOVE))(
       this.comment,
     ) as CommentMove;
     event.setReason(['drag']);