Fix #3014

- Add onBell event listener to allow embeders to hook into it

src/browser/Terminal.test.ts

@@ -131,6 +131,12 @@ describe('Terminal', () => {
       });
       term.write('\x1b]2;title\x07');
     });
+    it('should fire the onBell event', (done) => {
+      term.onBell(e => {       
+        done();
+      });
+      term.write('\a');
+    });
   });
 
   describe('attachCustomKeyEventHandler', () => {

src/browser/Terminal.ts

@@ -111,6 +111,8 @@ export class Terminal extends CoreTerminal implements ITerminal {
   public get onSelectionChange(): IEvent<void> { return this._onSelectionChange.event; }
   private _onTitleChange = new EventEmitter<string>();
   public get onTitleChange(): IEvent<string> { return this._onTitleChange.event; }
+  private _onBell  = new EventEmitter<void>();
+  public get onBell (): IEvent<void> { return this._onBell.event; }
 
   private _onFocus = new EventEmitter<void>();
   public get onFocus(): IEvent<void> { return this._onFocus.event; }
@@ -1141,6 +1143,8 @@ export class Terminal extends CoreTerminal implements ITerminal {
       this._soundService!.playBellSound();
     }
 
+    this._onBell.fire();
+    
     // if (this._visualBell()) {
     //   this.element.classList.add('visual-bell-active');
     //   clearTimeout(this._visualBellTimer);

src/browser/TestUtils.test.ts

@@ -37,6 +37,7 @@ export class MockTerminal implements ITerminal {
   public onData!: IEvent<string>;
   public onBinary!: IEvent<string>;
   public onTitleChange!: IEvent<string>;
+  public onBell!: IEvent<void>;
   public onScroll!: IEvent<number>;
   public onKey!: IEvent<{ key: string, domEvent: KeyboardEvent }>;
   public onRender!: IEvent<{ start: number, end: number }>;

src/browser/Types.d.ts

@@ -47,6 +47,7 @@ export interface IPublicTerminal extends IDisposable {
   onRender: IEvent<{ start: number, end: number }>;
   onResize: IEvent<{ cols: number, rows: number }>;
   onTitleChange: IEvent<string>;
+  onBell: IEvent<void>;
   blur(): void;
   focus(): void;
   resize(columns: number, rows: number): void;

src/browser/public/Terminal.ts

@@ -38,6 +38,7 @@ export class Terminal implements ITerminalApi {
   public get onData(): IEvent<string> { return this._core.onData; }
   public get onBinary(): IEvent<string> { return this._core.onBinary; }
   public get onTitleChange(): IEvent<string> { return this._core.onTitleChange; }
+  public get onBell(): IEvent<void> { return this._core.onBell; }
   public get onScroll(): IEvent<number> { return this._core.onScroll; }
   public get onKey(): IEvent<{ key: string, domEvent: KeyboardEvent }> { return this._core.onKey; }
   public get onRender(): IEvent<{ start: number, end: number }> { return this._core.onRender; }

src/common/Types.d.ts

@@ -357,6 +357,7 @@ export interface IAnsiColorChangeEvent {
  */
 export interface IInputHandler {
   onTitleChange: IEvent<string>;
+  onRequestBell: IEvent<void>;
 
   parse(data: string | Uint8Array, promiseResult?: boolean): void | Promise<boolean>;
   print(data: Uint32Array, start: number, end: number): void;

test/api/Terminal.api.ts

@@ -410,6 +410,16 @@ describe('API Integration Tests', function(): void {
       await page.evaluate(`window.term.write('\\x1b]2;foo\\x9c')`);
       await pollFor(page, `window.calls`, ['foo']);
     });
+    it('onBell', async () => {
+      await openTerminal(page);
+      await page.evaluate(`
+        window.calls = [];
+        window.term.onBell(e => window.calls.push(e));
+      `);
+      await pollFor(page, `window.calls`, []);
+      await page.evaluate(`window.term.write('\\a')`);
+      await pollFor(page, `window.calls`, ['foo']);
+    });
   });
 
   describe('buffer', () => {

typings/xterm.d.ts

@@ -708,6 +708,12 @@ declare module 'xterm' {
      * @returns an `IDisposable` to stop listening.
      */
     onTitleChange: IEvent<string>;
+    
+    /**
+     * Adds an event listener for when the bell sound.
+     * @returns an `IDisposable` to stop listening.
+     */
+     onBell: IEvent<void>;
 
     /**
      * Unfocus the terminal.