Merge pull request #10653 from IgniteUI/mkirkova/fix-10520-13.0.x

Emit panelCollapsing event once when a panel starts collapsing

Author: teodosiah

projects/igniteui-angular/src/lib/expansion-panel/expansion-panel.component.ts

@@ -225,7 +225,8 @@ export class IgxExpansionPanelComponent extends ToggleAnimationPlayer implements
      * ```
      */
     public collapse(evt?: Event) {
-        if (this.collapsed) { // If expansion panel is already collapsed, do nothing
+        // If expansion panel is already collapsed or is collapsing, do nothing
+        if (this.collapsed || this.closeAnimationPlayer) {
             return;
         }
         const args = { event: evt, panel: this, owner: this, cancel: false };

projects/igniteui-angular/src/lib/expansion-panel/expansion-panel.spec.ts

@@ -196,6 +196,16 @@ describe('igxExpansionPanel', () => {
             expect(panel.collapsed).toBeFalsy();
             expect(header.interaction.emit).toHaveBeenCalledTimes(4);
             expect(panel.contentCollapsed.emit).toHaveBeenCalledTimes(1);
+
+            // collapse when the panel has already started collapsing
+            header.onAction(mockEvent);
+            header.onAction(mockEvent);
+            tick();
+            fixture.detectChanges();
+
+            expect(panel.collapsed).toBeTruthy();
+            expect(header.interaction.emit).toHaveBeenCalledTimes(6);
+            expect(panel.contentCollapsing.emit).toHaveBeenCalledTimes(2);
         }));
 
         it('Should expand/collapse without animation when animationSettings === null', fakeAsync(() => {