feat(core): add support for <optgroup> tag

CHANGELOG.md

@@ -16,6 +16,18 @@ should change the heading of the (upcoming) version to include a major version b
 
 -->
 
+# 5.23.0
+
+## @rjsf/core
+
+- Updated `SelectWidget` to support `<optgroup>` through `ui:options` `optgroup`. Fixes [#1813]
+
+## @rjsf/playground
+
+- Updated `samples/widgets` to show `optgroup` usage (`selectWidgetOptions3`)
+
+## Dev / docs / playground
+
 # 5.22.4
 
 ## @rjsf/utils

packages/core/src/components/widgets/SelectWidget.tsx

@@ -39,7 +39,7 @@
   onFocus,
   placeholder,
 }: WidgetProps<T, S, F>) {
-  const { enumOptions, enumDisabled, emptyValue: optEmptyVal } = options;
+  const { enumOptions, enumDisabled, emptyValue: optEmptyVal, optgroups } = options;
   const emptyValue = multiple ? [] : '';
 
   const handleFocus = useCallback(
@@ -67,7 +67,37 @@
   );
 
   const selectedIndexes = enumOptionsIndexForValue<S>(value, enumOptions, multiple);
-  const showPlaceholderOption = !multiple && schema.default === undefined;
+
+  let opts = null
+  if (optgroups) {
+    let enumOptionFromValue = new Map()
+    enumOptions.forEach((enumOption, i) => {
+      enumOptionFromValue.set(enumOption.value, [enumOption, i])
+    })
+    opts = Object.keys(optgroups).map(optgroup => {
+      return (
+        <optgroup key={optgroup} label={optgroup}>{optgroups[optgroup].map(value => {
+          if (!enumOptionFromValue.has(value)) return null
+          const disabled = enumDisabled && enumDisabled.indexOf(value) !== -1;
+          let [{ label }, i] = enumOptionFromValue.get(value)
+          return (
+            <option key={i} value={String(i)} disabled={disabled}>
+              {label}
+            </option>
+          );
+        })}</optgroup>
+      )
+    })
+  } else {
+    opts = Array.isArray(enumOptions) && enumOptions.map(({ value, label }, i) => {
+      const disabled = enumDisabled && enumDisabled.indexOf(value) !== -1;
+      return (
+        <option key={i} value={String(i)} disabled={disabled}>
+          {label}
+        </option>
+      );
+    });
+  }
 
   return (
     <select
@@ -84,16 +114,8 @@
       onChange={handleChange}
       aria-describedby={ariaDescribedByIds<T>(id)}
     >
-      {showPlaceholderOption && <option value=''>{placeholder}</option>}
-      {Array.isArray(enumOptions) &&
-        enumOptions.map(({ value, label }, i) => {
-          const disabled = enumDisabled && enumDisabled.indexOf(value) !== -1;
-          return (
-            <option key={i} value={String(i)} disabled={disabled}>
-              {label}
-            </option>
-          );
-        })}
+      {!multiple && schema.default === undefined && <option value=''>{placeholder}</option>}
+      {opts}
     </select>
   );
 }

packages/docs/docs/api-reference/uiSchema.md

@@ -344,6 +344,32 @@ render(<Form schema={schema} uiSchema={uiSchema} validator={validator} />, docum
 
 This property allows you to reorder the properties that are shown for a particular object. See [Objects](../json-schema/objects.md) for more information.
 
+### optgroup
+
+To leverage `<optgroup>` inside a select to group `<options>`, you can specify how to organize the options using the `optgroups` key inside your uiSchema.
+
+```tsx
+import { Form } from '@rjsf/core';
+import { RJSFSchema, UiSchema } from '@rjsf/utils';
+import validator from '@rjsf/validator-ajv8';
+
+const schema: RJSFSchema = {
+  type: 'string',
+  enum: ['lorem', 'ipsum', 'dolorem', 'alpha', 'beta', 'gamma']
+};
+
+const uiSchema: UiSchema = {
+  'ui:options': {
+    optgroups: {
+      lipsum: ['lorem', 'ipsum', 'dolorem'],
+      greek: ['alpha', 'beta', 'gamma']
+    }
+  },
+};
+
+render(<Form schema={schema} uiSchema={uiSchema} validator={validator} />, document.getElementById('app'));
+```
+
 ### placeholder
 
 You can add placeholder text to an input by using the `ui:placeholder` uiSchema directive:

packages/playground/src/samples/widgets.tsx

@@ -106,6 +106,11 @@ const widgets: Sample = {
           },
         ],
       },
+      selectWidgetOptions3: {
+        title: 'Custom select widget with options grouped by optgroups',
+        type: 'string',
+        enum: ['foo', 'bar'],
+      },
     },
   },
   uiSchema: {
@@ -196,6 +201,14 @@ const widgets: Sample = {
         backgroundColor: 'pink',
       },
     },
+    selectWidgetOptions3: {
+      'ui:options': {
+        'optgroups': {
+          'lipsum': ['foo'],
+          'dolorem': ['bar']
+        }
+      }
+    }
   },
   formData: {
     stringFormats: {