Fix pop-value being sent for undefined values. (#5960)

* Fix pop-value being sent for undefined values.

* Fix unit tests.

* Fix linting.

* Add changeset.

.changeset/calm-snakes-collect.md

@@ -0,0 +1,5 @@
+---
+'react-select': patch
+---
+
+No longer send pop-value action when multi-select is empty. This correctly resolves typings with that event, where removedValue cannot be undefined.

packages/react-select/src/Select.tsx

@@ -1096,10 +1096,12 @@ export default class Select<
       newValueArray[0] || null
     );
 
-    this.onChange(newValue, {
-      action: 'pop-value',
-      removedValue: lastSelectedValue,
-    });
+    if (lastSelectedValue) {
+      this.onChange(newValue, {
+        action: 'pop-value',
+        removedValue: lastSelectedValue,
+      });
+    }
   };
 
   // ==============================

packages/react-select/src/__tests__/Select.test.tsx

@@ -1906,6 +1906,7 @@ test('should call onChange with an array on hitting backspace when backspaceRemo
       isClearable
       isMulti
       onChange={onChangeSpy}
+      value={[OPTIONS[0]]}
     />
   );
   fireEvent.keyDown(container.querySelector('.react-select__control')!, {
@@ -1915,10 +1916,28 @@ test('should call onChange with an array on hitting backspace when backspaceRemo
   expect(onChangeSpy).toHaveBeenCalledWith([], {
     action: 'pop-value',
     name: 'test-input-name',
-    removedValue: undefined,
+    removedValue: OPTIONS[0],
   });
 });
 
+test('should call not call onChange on hitting backspace when backspaceRemovesValue is true and isMulti is true and there are no values', () => {
+  let onChangeSpy = jest.fn();
+  let { container } = render(
+    <Select
+      {...BASIC_PROPS}
+      backspaceRemovesValue
+      isClearable
+      isMulti
+      onChange={onChangeSpy}
+    />
+  );
+  fireEvent.keyDown(container.querySelector('.react-select__control')!, {
+    keyCode: 8,
+    key: 'Backspace',
+  });
+  expect(onChangeSpy).not.toHaveBeenCalled();
+});
+
 test('multi select > clicking on X next to option will call onChange with all options other that the clicked option', () => {
   let onChangeSpy = jest.fn();
   let { container } = render(