misc form row fixes

CHANGELOG.md

@@ -6,13 +6,15 @@
 - Added `numActiveFilters` prop to `EuiFilterButton` ([#1589](https://github.com/elastic/eui/pull/1589))
 - Updated style of `EuiFilterButton` to match `EuiFacetButton` ([#1589](https://github.com/elastic/eui/pull/1589))
 - Added `size` and `color` props to `EuiNotificationBadge` ([#1589](https://github.com/elastic/eui/pull/1589))
+- Allow `EuiDescribedFormGroup` to exist as a description-only row ([#1522](https://github.com/elastic/eui/pull/1522))
 
 **Bug fixes**
 
 - `EuiBasicTable` select all shows up on mobile ([#1462](https://github.com/elastic/eui/pull/1462))
 - Adds missing `hasActiveFilters` prop for `EuiFilterButton` type and fixes `onChange` signature for `EuiButtonGroup` ([#1603](https://github.com/elastic/eui/pull/1603))
 - Included `react-datepicker` TS types in EUI itself to avoid outside dependency ([#1618](https://github.com/elastic/eui/pull/1618))
 - Prevent `EuiGlobalToastList` from attempting calculations on `null` DOM elements ([#1606](https://github.com/elastic/eui/pull/1606))
+- Fixed `EuiFormRow` errors from the possibility of having duplicate `key` values ([#1522](https://github.com/elastic/eui/pull/1522)) 
 
 **Breaking changes**
 

src/components/form/described_form_group/described_form_group.js

@@ -101,7 +101,7 @@ EuiDescribedFormGroup.propTypes = {
   /**
    * One or more `EuiFormRow`s
    */
-  children: PropTypes.node.isRequired,
+  children: PropTypes.node,
   className: PropTypes.string,
   /**
    * Passed to `EuiFlexGroup`

src/components/form/form_row/form_row.js

@@ -93,11 +93,14 @@ export class EuiFormRow extends Component {
 
     if (error && isInvalid) {
       const errorTexts = Array.isArray(error) ? error : [error];
-      optionalErrors = errorTexts.map((error, i) => (
-        <EuiFormErrorText key={error} id={`${id}-error-${i}`} className="euiFormRow__text">
-          {error}
-        </EuiFormErrorText>
-      ));
+      optionalErrors = errorTexts.map((error, i) =>{
+        const key = typeof error === 'string' ? error : i;
+        return (
+          <EuiFormErrorText key={key} id={`${id}-error-${i}`} className="euiFormRow__text">
+            {error}
+          </EuiFormErrorText>
+        );}
+      );
     }
 
     let optionalLabel;