fix(simple-combo): filter on typing when combo is focused but not opened

Author: georgianastasov

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

@@ -1528,6 +1528,23 @@ describe('IgxSimpleCombo', () => {
             expect(combo.filteredData.length).toBeLessThan(combo.data.length)
             expect(combo.filteredData[0].field).toBe(target.value)
         });
+
+        it('should properly filter dropdown when a key is pressed while the combo is focused but not opened', fakeAsync(() => {
+            spyOn(combo, 'open').and.callThrough();
+
+            const event = UIInteractions.getKeyboardEvent('keydown', 'z');
+
+            expect(combo.collapsed).toEqual(true);
+
+            combo.handleKeyDown(event);
+            tick();
+            fixture.detectChanges();
+
+            expect(combo.collapsed).toEqual(false);
+            expect(combo.open).toHaveBeenCalled();
+            expect(combo.filteredData.length).toEqual(1);
+            expect(combo.filteredData).toEqual([{ field: 'Arizona', region: 'Mount' }]);
+        }));
     });
 
     describe('Display density', () => {

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

@@ -327,15 +327,23 @@ export class IgxSimpleComboComponent extends IgxComboBaseDirective implements Co
             // manually trigger text selection as it will not be triggered during editing
             this.textSelection.trigger();
             return;
-        }
-        if (event.key === this.platformUtil.KEYMAP.BACKSPACE
+        } else if (event.key === this.platformUtil.KEYMAP.BACKSPACE
             || event.key === this.platformUtil.KEYMAP.DELETE) {
             this._updateInput = false;
             this.clearSelection(true);
-        }
-        if (!this.collapsed && event.key === this.platformUtil.KEYMAP.TAB) {
+        } else if (event.key === this.platformUtil.KEYMAP.TAB) {
             this.clearOnBlur();
             this.close();
+        } else {
+            if (event.key !== this.platformUtil.KEYMAP.ARROW_DOWN && event.key !== this.platformUtil.KEYMAP.SPACE) {
+                const newFilterValue = this.filterValue + event.key.toLowerCase();
+                this.filterValue = newFilterValue;
+                this.searchValue = newFilterValue;
+                this.filteredData = this.data.filter(item => this.findAllMatches(item));
+                if (this.filteredData.length > 0 && this.collapsed) {
+                    this.open();
+                }
+            }
         }
         this.composing = false;
         super.handleKeyDown(event);