fix(simple-combo): trigger selectionChanging on input clear

Author: georgianastasov

projects/igniteui-angular/src/lib/simple-combo/simple-combo.component.spec.ts

@@ -1528,6 +1528,48 @@ describe('IgxSimpleCombo', () => {
             expect(combo.filteredData.length).toBeLessThan(combo.data.length)
             expect(combo.filteredData[0].field).toBe(target.value)
         });
+
+        it('should emit selectionChanging event when input value changes and input loses focus', () => {
+            spyOn(combo.selectionChanging, 'emit').and.callThrough();
+            fixture.detectChanges();
+
+            combo.select('Connecticut');
+            fixture.detectChanges();
+
+            expect(combo.selectionChanging.emit).toHaveBeenCalledTimes(1);
+            expect(combo.selectionChanging.emit).toHaveBeenCalledWith({
+                newValue: "Connecticut",
+                oldValue: undefined,
+                newSelection: {
+                    field: "Connecticut",
+                    region: "New England"
+                },
+                oldSelection: undefined,
+                displayText: 'Connecticut',
+                owner: combo,
+                cancel: false
+            });
+
+            combo.handleInputChange('z');
+            fixture.detectChanges();
+
+            combo.onBlur();
+            fixture.detectChanges();
+
+            expect(combo.selectionChanging.emit).toHaveBeenCalledTimes(2);
+            expect(combo.selectionChanging.emit).toHaveBeenCalledWith({
+                oldValue: "Connecticut",
+                newValue: undefined,
+                oldSelection: {
+                    field: "Connecticut",
+                    region: "New England"
+                },
+                newSelection: undefined,
+                owner: combo,
+                displayText: "",
+                cancel: false
+            });
+        });
     });
 
     describe('Display density', () => {

projects/igniteui-angular/src/lib/simple-combo/simple-combo.component.ts

@@ -115,6 +115,8 @@ export class IgxSimpleComboComponent extends IgxComboBaseDirective implements Co
 
     private _collapsing = false;
 
+    private _previousSelection = { selectedItem: '', selection: [] };
+
     /** @hidden @internal */
     public get filteredData(): any[] | null {
         return this._filteredData;
@@ -279,6 +281,9 @@ export class IgxSimpleComboComponent extends IgxComboBaseDirective implements Co
 
     /** @hidden @internal */
     public override handleInputChange(event?: any): void {
+        if (this.hasSelectedItem) {
+            this._previousSelection = { selectedItem: this.selectedItem, selection: this.selection };
+        }
         if (event !== undefined) {
             this.filterValue = this.searchValue = typeof event === 'string' ? event : event.target.value;
         }
@@ -466,6 +471,10 @@ export class IgxSimpleComboComponent extends IgxComboBaseDirective implements Co
         };
         if (args.newSelection !== args.oldSelection) {
             this.selectionChanging.emit(args);
+        } else if (this._updateInput && newSelection.size === 0 && this._previousSelection.selectedItem !== '') {
+            args.oldValue = this._previousSelection.selectedItem;
+            args.oldSelection = this._previousSelection.selection;
+            this.selectionChanging.emit(args);
         }
         // TODO: refactor below code as it sets the selection and the display text
         if (!args.cancel) {
@@ -482,9 +491,15 @@ export class IgxSimpleComboComponent extends IgxComboBaseDirective implements Co
             }
             this._onChangeCallback(args.newValue);
             this._updateInput = true;
+        } else if (args.cancel) {
+            if (this._updateInput && this._previousSelection.selectedItem !== '') {
+                this.selectionService.select_items(this.id, [this._previousSelection.selectedItem], true);
+                this._value = [this._previousSelection.selectedItem];
+            }
         } else if (this.isRemote) {
             this.registerRemoteEntries(newValueAsArray, false);
-        }
+        } 
+        this._previousSelection = { selectedItem: '', selection: [] };
     }
 
     protected createDisplayText(newSelection: any[], oldSelection: any[]): string {