Fix bug in EuiComboBox's inputRef callback (elastic#3532)

* Fix bug in EuiComboBox's inputRef callback

* changelog

CHANGELOG.md

@@ -19,6 +19,7 @@
 - Fixed `EuiBasicTable` shows no items if all items of last page is deleted  ([#3422](https://github.com/elastic/eui/pull/3422))
 - Fixed TypeScript module name in generated `eui_charts_theme.d.ts` file  ([#3492](https://github.com/elastic/eui/pull/3492))
 - Fixed code highlight color contrast in `EuiCodeBlock` ([#3309](https://github.com/elastic/eui/pull/3309))
+- Fixed regression in `EuiComboBox` not triggering its `inputRef` callback ([#3532](https://github.com/elastic/eui/pull/3532))
 
 **Deprecations**
 

src/components/combo_box/combo_box.test.tsx

@@ -372,4 +372,19 @@ describe('behavior', () => {
       expect(component.state('matchingOptions')[0].label).toBe('Enceladus');
     });
   });
+
+  it('calls the inputRef prop with the input element', () => {
+    const inputRefCallback = jest.fn();
+
+    const component = mount<
+      EuiComboBox<TitanOption>,
+      EuiComboBoxProps<TitanOption>,
+      { matchingOptions: TitanOption[] }
+    >(<EuiComboBox options={options} inputRef={inputRefCallback} />);
+
+    expect(inputRefCallback).toHaveBeenCalledTimes(1);
+    expect(component.find('input[role="textbox"]').getDOMNode()).toBe(
+      inputRefCallback.mock.calls[0][0]
+    );
+  });
 });

src/components/combo_box/combo_box.tsx

@@ -257,6 +257,7 @@ export class EuiComboBox<T> extends Component<
   searchInputRefInstance: RefInstance<HTMLInputElement> = null;
   searchInputRefCallback: RefCallback<HTMLInputElement> = ref => {
     this.searchInputRefInstance = ref;
+    if (this.props.inputRef) this.props.inputRef(ref);
   };
 
   listRefInstance: RefInstance<HTMLDivElement> = null;