feat(events): re-fire the tabchange and change events to expose them as non-bubbling

README.md

@@ -756,6 +756,13 @@ All-in-one project, editor, file switcher, and preview with a horizontal side-by
 | `default`    | Inline files ([details](#inline-scripts)).                            |
 | `extensions` | Declarative CodeMirror extensions ([details](#extending-the-editor)). |
 
+### Events
+
+| Event       | Description                                                                                                                                        |
+| ----------- | -------------------------------------------------------------------------------------------------------------------------------------------------- |
+| `tabchange` | A tab has been activated.                                                                                                                          |
+| `change`    | User made an edit to the active file (note: this event is not fired for programmatic changes to the value property nor for the user changing tabs) |
+
 ---
 
 ## `<playground-project>`
@@ -813,6 +820,12 @@ project element.
 
 ---
 
+### Events
+
+| Event       | Description               |
+| ----------- | ------------------------- |
+| `tabchange` | A tab has been activated. |
+
 ## `<playground-file-editor>`
 
 ### Properties
@@ -834,6 +847,12 @@ project element.
 | ------------ | --------------------------------------------------------------------- |
 | `extensions` | Declarative CodeMirror extensions ([details](#extending-the-editor)). |
 
+### Events
+
+| Event    | Description                                                                                                                                        |
+| -------- | -------------------------------------------------------------------------------------------------------------------------------------------------- |
+| `change` | User made an edit to the active file (note: this event is not fired for programmatic changes to the value property nor for the user changing tabs) |
+
 ---
 
 ## `<playground-code-editor>`

src/playground-file-editor.ts

@@ -15,6 +15,7 @@ import {Extension} from '@codemirror/state';
 import {PlaygroundProject} from './playground-project.js';
 import {PlaygroundCodeEditor} from './playground-code-editor.js';
 import {CodeEditorChangeData} from './shared/worker-api.js';
+import {refireEvent} from './shared/util.js';
 
 /**
  * A text editor associated with a <playground-project>.
@@ -172,7 +173,7 @@ export class PlaygroundFileEditor extends PlaygroundConnectedElement {
               )}
               .extensions=${this.extensions}
               .noCompletions=${this.noCompletions}
-              @change=${this._onEdit}
+              @change=${this._onChange}
               @request-completions=${this._onRequestCompletions}
             >
               <slot name="extensions" slot="extensions"></slot>
@@ -197,7 +198,7 @@ export class PlaygroundFileEditor extends PlaygroundConnectedElement {
     this.requestUpdate();
   };
 
-  private _onEdit() {
+  private _onChange(event: Event) {
     if (
       this._project === undefined ||
       this._currentFile === undefined ||
@@ -206,6 +207,8 @@ export class PlaygroundFileEditor extends PlaygroundConnectedElement {
       return;
     }
     this._project.editFile(this._currentFile, this._editor.value);
+    // Re-fire the change event on the host element for external consumers
+    refireEvent(this, event);
   }
 
   private async _onRequestCompletions(e: CustomEvent) {

src/playground-ide.ts

@@ -15,6 +15,7 @@ import './playground-preview.js';
 import {PlaygroundProject} from './playground-project.js';
 import {ProjectManifest} from './shared/worker-api.js';
 import {npmVersion, serviceWorkerHash} from './shared/version.js';
+import {refireEvent} from './shared/util.js';
 
 /**
  * A multi-file code editor component with live preview that works without a
@@ -327,6 +328,7 @@ export class PlaygroundIde extends LitElement {
           .project=${projectId}
           .editor=${editorId}
           .editableFileSystem=${this.editableFileSystem}
+          @tabchange=${this._onTabChange}
         >
         </playground-tab-bar>
 
@@ -339,6 +341,7 @@ export class PlaygroundIde extends LitElement {
           .pragmas=${this.pragmas}
           .noCompletions=${this.noCompletions}
           .extensions=${this.extensions}
+          @change=${this._onChange}
         >
           <slot name="extensions" slot="extensions"></slot>
         </playground-file-editor>
@@ -388,6 +391,16 @@ export class PlaygroundIde extends LitElement {
     super.update(changedProperties);
   }
 
+  private _onTabChange(event: Event) {
+    // Re-fire the tabchange event on the host element for external consumers
+    refireEvent(this, event);
+  }
+
+  private _onChange(event: Event) {
+    // Re-fire the change event on the host element for external consumers
+    refireEvent(this, event);
+  }
+
   private _onResizeBarPointerdown({pointerId}: PointerEvent) {
     const bar = this._resizeBar;
     bar.setPointerCapture(pointerId);

src/playground-tab-bar.ts

@@ -18,6 +18,7 @@ import {PlaygroundConnectedElement} from './playground-connected-element.js';
 import {PlaygroundFileEditor} from './playground-file-editor.js';
 import {PlaygroundFileSystemControls} from './playground-file-system-controls.js';
 import {FilesChangedEvent, PlaygroundProject} from './playground-project.js';
+import {refireEvent} from './shared/util.js';
 import {PlaygroundInternalTab} from './internal/tab.js';
 
 /**
@@ -257,6 +258,13 @@ export class PlaygroundTabBar extends PlaygroundConnectedElement {
     if (name !== this._activeFileName) {
       this._activeFileName = name;
       this._activeFileIndex = index;
+      // Re-fire the tabchange event on the host element for external consumers
+      refireEvent(
+        this,
+        new CustomEvent('tabchange', {
+          detail: {filename: name},
+        })
+      );
     }
   }
 

src/shared/util.ts

@@ -28,3 +28,23 @@ export const forceSkypackRawMode = (url: URL): URL => {
 export type Result<V, E> =
   | {result: V; error?: undefined}
   | {result?: undefined; error: E};
+
+/**
+ * Re-fires an event on the given element, without bubbles or composed flags.
+ * This is useful for re-firing internal events on public component boundaries
+ * to avoid them crossing shadow DOM boundaries while still making them available
+ * to external consumers.
+ */
+export const refireEvent = (
+  element: EventTarget,
+  event: Event | CustomEvent
+): void => {
+  const detail = (event as CustomEvent).detail;
+  element.dispatchEvent(
+    new CustomEvent(event.type, {
+      detail,
+      bubbles: false,
+      composed: false,
+    })
+  );
+};