fix: clear selection when masked input is cleared on blur

src/index.tsx

@@ -707,6 +707,20 @@ export class DatePicker extends Component<DatePickerProps, DatePickerState> {
       this.props.onBlur?.(event);
     }
 
+    // If user cleared the input via a mask library (inputValue has no date-like
+    // characters), clear the selection on blur (fixes issue #5814 with mask inputs)
+    const { inputValue } = this.state;
+    if (typeof inputValue === "string" && inputValue.length > 0) {
+      // Check if input looks like a cleared mask (no alphanumeric characters)
+      // This distinguishes between:
+      // - "__/__/____" (cleared mask) → should clear selection
+      // - "2025-02-45" (invalid date) → should keep previous selection
+      const hasDateCharacters = /[a-zA-Z0-9]/.test(inputValue);
+      if (!hasDateCharacters && this.props.selected) {
+        this.setSelected(null, undefined, true);
+      }
+    }
+
     this.resetInputValue();
 
     if (this.state.open && this.props.open === false) {

src/test/datepicker_test.test.tsx

@@ -2447,6 +2447,78 @@ describe("DatePicker", () => {
 
     expect(onChangeSpy.mock.calls.at(-1)[0]).toStrictEqual([null, null]);
   });
+  it("should keep input cleared after blur when using controlled component (issue #5814)", () => {
+    function ControlledDatePicker() {
+      const [selected, setSelected] = useState<Date | null>(
+        newDate("2024-12-25"),
+      );
+
+      return (
+        <DatePicker
+          selected={selected}
+          onChange={(date: Date | null) => setSelected(date)}
+          dateFormat="MM/dd/yyyy"
+        />
+      );
+    }
+
+    const { container } = render(<ControlledDatePicker />);
+    const input = safeQuerySelector<HTMLInputElement>(container, "input");
+
+    // Initial value should be the formatted date
+    expect(input.value).toBe("12/25/2024");
+
+    // Clear the input
+    fireEvent.change(input, { target: { value: "" } });
+
+    // Blur the input
+    fireEvent.blur(input);
+
+    // After blur, the input should still be empty (not revert to the date)
+    expect(input.value).toBe("");
+  });
+  it("should handle mask pattern clearing (issue #5814)", () => {
+    // Mask libraries often show "__/__/____" when cleared instead of empty string
+    const onChangeSpy = jest.fn();
+
+    function MaskedDatePicker() {
+      const [selected, setSelected] = useState<Date | null>(
+        newDate("2024-12-25"),
+      );
+
+      const handleChange = (date: Date | null) => {
+        onChangeSpy(date);
+        setSelected(date);
+      };
+
+      return (
+        <DatePicker
+          selected={selected}
+          onChange={handleChange}
+          dateFormat="MM/dd/yyyy"
+        />
+      );
+    }
+
+    const { container } = render(<MaskedDatePicker />);
+    const input = safeQuerySelector<HTMLInputElement>(container, "input");
+
+    // Initial value should be the formatted date
+    expect(input.value).toBe("12/25/2024");
+
+    // Simulate mask library clearing - value becomes mask pattern, not empty
+    fireEvent.change(input, { target: { value: "__/__/____" } });
+
+    // onChange should NOT be called with null because mask pattern isn't a valid date
+    // But it also shouldn't be called with the old date
+    // The key issue: what happens on blur?
+
+    fireEvent.blur(input);
+
+    // The input should show the mask pattern, not revert to the old date
+    // This is where the bug manifests - in React 18, it might revert
+    expect(input.value).not.toBe("12/25/2024");
+  });
   it("should update preSelection when input changes for selectsRange", () => {
     let instance: DatePicker | null = null;
     const onChangeSpy = jest.fn();