[EuiSuperDatePicker] More forgiving absolute input

packages/eui/changelogs/upcoming/9199.md

@@ -0,0 +1,2 @@
+- Updated `EuiSuperDatePicker` to have a more forgiving manual input for absolute dates.
+

packages/eui/src/components/date_picker/super_date_picker/date_popover/absolute_tab.test.tsx

@@ -123,6 +123,31 @@ describe('EuiAbsoluteTab', () => {
       expect(input).toHaveValue('Jan 31st 01');
     });
 
+    it('can be forgiving with `dateFormat`', () => {
+      const { getByTestSubject } = render(
+        <EuiAbsoluteTab
+          {...props}
+          dateFormat="MMM D, YYYY HH:mm:ss"
+          locale="en"
+        />
+      );
+      const input = getByTestSubject(
+        'superDatePickerAbsoluteDateInput'
+      ) as HTMLInputElement;
+
+      changeInput(input, 'Jan 31, 1993');
+      expect(input).not.toBeInvalid();
+      expect(input).toHaveValue('Jan 31, 1993 00:00:00');
+
+      changeInput(input, 'Jan 31');
+      expect(input).not.toBeInvalid();
+      expect(input.value).toContain('Jan 31, ');
+
+      changeInput(input, 'Jan');
+      expect(input).not.toBeInvalid();
+      expect(input.value).toContain('Jan 1, ');
+    });
+
     describe('parses date string in locale', () => {
       test.each<{
         locale: LocaleSpecifier;

packages/eui/src/components/date_picker/super_date_picker/date_popover/absolute_tab.tsx

@@ -126,12 +126,22 @@ export const EuiAbsoluteTab: FunctionComponent<EuiAbsoluteTabProps> = ({
         return;
       }
 
+      // We can be forgiving for `dateFormat` if we are certain
+      // we're not expecting any of the other formats allowed;
+      // otherwise we can get valid but inaccurate results e.g.
+      // `1970-01-01` -> `Jan 19, 1970 @ 01:01:00.000`
+      const strictModeForPassedFormat = moment(
+        textInputValue,
+        ALLOWED_USER_DATE_FORMATS,
+        true
+      ).isValid();
+
       // Attempt to parse with passed `dateFormat` and `locale`
       let valueAsMoment = moment(
         textInputValue,
         dateFormat,
         typeof locale === 'string' ? locale : 'en', // Narrow the union type to string
-        true
+        strictModeForPassedFormat
       );
       let dateIsValid = valueAsMoment.isValid();