feat(editor): add the onOpenTab event (#416)

* feat(editor): add the onOpenTab event

* test(editor): unit test for the onOpenTab event

Author: wewoor

src/services/workbench/__tests__/editorService.test.tsx

@@ -55,6 +55,17 @@ describe('Test EditorService', () => {
         ).not.toBeUndefined();
     });
 
+    test('Listen to the tab opening event', () => {
+        const editor = new EditorService();
+        expectFnCalled((fun) => {
+            editor.onOpenTab(fun);
+            // Open in default Group
+            editor.open(mockTab);
+
+            expect(fun.mock.calls[0][0]).toEqual(mockTab);
+        });
+    });
+
     test('Get the default editor options', () => {
         const editor = new EditorService();
         expect(editor.getDefaultEditorOptions()).toEqual(BuiltInEditorOptions);

src/services/workbench/editorService.ts

@@ -94,6 +94,11 @@ export interface IEditorService extends Component<IEditor> {
      * @param callback
      */
     onUpdateTab(callback: (tab: IEditorTab) => void): void;
+    /**
+     * Listen to the tab opening event
+     * @param callback
+     */
+    onOpenTab(callback: (tab: IEditorTab) => void): void;
     /**
      * Listen to the tab move event
      * @param callback
@@ -562,12 +567,18 @@ export class EditorService
             groups.push(group);
         }
 
+        this.emit(EditorEvent.OpenTab, tab);
+
         this.setState({
             current: group,
             groups: [...groups],
         });
     }
 
+    public onOpenTab(callback: (tab: IEditorTab) => void): void {
+        this.subscribe(EditorEvent.OpenTab, callback);
+    }
+
     public closeAll(groupId: number) {
         const { current, groups = [] } = this.state;
         const groupIndex = this.getGroupIndexById(groupId);