Feature: expanded FallbackField for object and array

CHANGELOG.md

@@ -30,9 +30,10 @@ should change the heading of the (upcoming) version to include a major version b
 ## @rjsf/core
 
 - Fixed duplicate label and description rendering in `CheckboxWidget` by conditionally rendering them based on widget type
-    - Updated `CheckboxWidget` to handle label and description rendering consistently
-    - Modified `FieldTemplate` to skip label and description rendering for checkbox widgets, fixing ([#4742](https://github.com/rjsf-team/react-jsonschema-form/issues/4742))
+  - Updated `CheckboxWidget` to handle label and description rendering consistently
+  - Modified `FieldTemplate` to skip label and description rendering for checkbox widgets, fixing ([#4742](https://github.com/rjsf-team/react-jsonschema-form/issues/4742))
 - Updated `ObjectField` to change the removal of an additional property to defer the work to the `processPendingChange()` handler in `Form`, fixing [#4850](https://github.com/rjsf-team/react-jsonschema-form/issues/4850)
+- Updated `FallbackField` to support `object` and `array` types, and improved `ArrayField` so that it handles missing items properly with the fallback field
 
 ## @rjsf/fluentui-rc
 
@@ -66,7 +67,6 @@ should change the heading of the (upcoming) version to include a major version b
 ## @rjsf/utils
 
 - Updated `getDefaultFormState()` to not save an undefined field value into an object when the type is `null` and `excludeObjectChildren` is provided, fixing [#4821](https://github.com/rjsf-team/react-jsonschema-form/issues/4821)
-- Added new `ADDITIONAL_PROPERTY_KEY_REMOVE` constant
 
 ## Dev / docs / playground
 

packages/core/src/components/Form.tsx

@@ -1,6 +1,5 @@
 import { Component, ElementType, FormEvent, ReactNode, Ref, RefObject, createRef } from 'react';
 import {
-  ADDITIONAL_PROPERTY_KEY_REMOVE,
   createSchemaUtils,
   CustomValidator,
   deepEquals,
@@ -55,9 +54,7 @@ import _toPath from 'lodash/toPath';
 import _unset from 'lodash/unset';
 
 import getDefaultRegistry from '../getDefaultRegistry';
-
-/** Internal only symbol used by the `reset()` function to indicate that a reset operation is happening */
-const IS_RESET = Symbol('reset');
+import { ADDITIONAL_PROPERTY_KEY_REMOVE, IS_RESET } from './constants';
 
 /** The properties that are passed to the `Form` */
 export interface FormProps<T = any, S extends StrictRJSFSchema = RJSFSchema, F extends FormContextType = any> {

packages/core/src/components/constants.ts

@@ -0,0 +1,5 @@
+/** Internal only symbol used by `Form` & `ObjectField` to mark an additional property element to be removed */
+export const ADDITIONAL_PROPERTY_KEY_REMOVE = Symbol('remove-this-key');
+
+/** Internal only symbol used by the `reset()` function to indicate that a reset operation is happening */
+export const IS_RESET = Symbol('reset');

packages/core/src/components/fields/ArrayField.tsx

@@ -153,9 +153,12 @@ function getNewFormDataRow<T = any, S extends StrictRJSFSchema = RJSFSchema, F e
   registry: Registry<T[], S, F>,
   schema: S,
 ): T {
-  const { schemaUtils } = registry;
+  const { schemaUtils, globalFormOptions } = registry;
   let itemSchema = schema.items as S;
-  if (isFixedItems(schema) && allowAdditionalItems(schema)) {
+  if (globalFormOptions.useFallbackUiForUnsupportedType && !itemSchema) {
+    // If we don't have itemSchema and useFallbackUiForUnsupportedType is on, use an empty schema
+    itemSchema = {} as S;
+  } else if (isFixedItems(schema) && allowAdditionalItems(schema)) {
     itemSchema = schema.additionalItems as S;
   }
   // Cast this as a T to work around schema utils being for T[] caused by the FieldProps<T[], S, F> call on the class
@@ -840,7 +843,7 @@ export default function ArrayField<T = any, S extends StrictRJSFSchema = RJSFSch
   props: FieldProps<T[], S, F>,
 ) {
   const { schema, uiSchema, errorSchema, fieldPathId, registry, formData, onChange } = props;
-  const { schemaUtils, translateString } = registry;
+  const { globalFormOptions, schemaUtils, translateString } = registry;
   const { keyedFormData, updateKeyedFormData } = useKeyedFormData<T>(formData);
   // All the children will use childFieldPathId if present in the props, falling back to the fieldPathId
   const childFieldPathId = props.childFieldPathId ?? fieldPathId;
@@ -1027,43 +1030,56 @@ export default function ArrayField<T = any, S extends StrictRJSFSchema = RJSFSch
     [onChange, childFieldPathId],
   );
 
-  if (!(ITEMS_KEY in schema)) {
-    const uiOptions = getUiOptions<T[], S, F>(uiSchema);
-    const UnsupportedFieldTemplate = getTemplate<'UnsupportedFieldTemplate', T[], S, F>(
-      'UnsupportedFieldTemplate',
-      registry,
-      uiOptions,
-    );
-
-    return (
-      <UnsupportedFieldTemplate
-        schema={schema}
-        fieldPathId={fieldPathId}
-        reason={translateString(TranslatableString.MissingItems)}
-        registry={registry}
-      />
-    );
-  }
-  const arrayProps = {
+  const arrayAsMultiProps: ArrayAsFieldProps<T[], S, F> = {
+    ...props,
+    formData,
+    fieldPathId: childFieldPathId,
+    onSelectChange: onSelectChange,
+  };
+  const arrayProps: InternalArrayFieldProps<T, S, F> = {
+    ...props,
     handleAddItem,
     handleCopyItem,
     handleRemoveItem,
     handleReorderItems,
     keyedFormData,
     onChange: handleChange,
   };
-  if (schemaUtils.isMultiSelect(schema)) {
+  if (!(ITEMS_KEY in schema)) {
+    if (!globalFormOptions.useFallbackUiForUnsupportedType) {
+      const uiOptions = getUiOptions<T[], S, F>(uiSchema);
+      const UnsupportedFieldTemplate = getTemplate<'UnsupportedFieldTemplate', T[], S, F>(
+        'UnsupportedFieldTemplate',
+        registry,
+        uiOptions,
+      );
+
+      return (
+        <UnsupportedFieldTemplate
+          schema={schema}
+          fieldPathId={fieldPathId}
+          reason={translateString(TranslatableString.MissingItems)}
+          registry={registry}
+        />
+      );
+    }
+    // Add an items schema with type as undefined so it triggers FallbackField later on
+    const fallbackSchema = { ...schema, [ITEMS_KEY]: { type: undefined } };
+    arrayAsMultiProps.schema = fallbackSchema;
+    arrayProps.schema = fallbackSchema;
+  }
+  if (schemaUtils.isMultiSelect(arrayAsMultiProps.schema)) {
     // If array has enum or uniqueItems set to true, call renderMultiSelect() to render the default multiselect widget or a custom widget, if specified.
-    return <ArrayAsMultiSelect<T, S, F> {...props} fieldPathId={childFieldPathId} onSelectChange={onSelectChange} />;
+    return <ArrayAsMultiSelect<T, S, F> {...arrayAsMultiProps} />;
   }
   if (isCustomWidget<T[], S, F>(uiSchema)) {
-    return <ArrayAsCustomWidget<T, S, F> {...props} fieldPathId={childFieldPathId} onSelectChange={onSelectChange} />;
+    return <ArrayAsCustomWidget<T, S, F> {...arrayAsMultiProps} />;
   }
-  if (isFixedItems(schema)) {
-    return <FixedArray<T, S, F> {...props} {...arrayProps} />;
+  if (isFixedItems(arrayAsMultiProps.schema)) {
+    return <FixedArray<T, S, F> {...arrayProps} />;
   }
-  if (schemaUtils.isFilesArray(schema, uiSchema)) {
-    return <ArrayAsFiles {...props} fieldPathId={childFieldPathId} onSelectChange={onSelectChange} />;
+  if (schemaUtils.isFilesArray(arrayAsMultiProps.schema, uiSchema)) {
+    return <ArrayAsFiles<T, S, F> {...arrayAsMultiProps} />;
   }
-  return <NormalArray<T, S, F> {...props} {...arrayProps} />;
+  return <NormalArray<T, S, F> {...arrayProps} />;
 }

packages/core/src/components/fields/FallbackField.tsx

@@ -21,7 +21,7 @@ import { JSONSchema7TypeName } from 'json-schema';
 function getFallbackTypeSelectionSchema(title: string): RJSFSchema {
   return {
     type: 'string',
-    enum: ['string', 'number', 'boolean'],
+    enum: ['string', 'number', 'boolean', 'object', 'array'],
     default: 'string',
     title: title,
   };
@@ -36,6 +36,9 @@ function getTypeOfFormData(formData: any): JSONSchema7TypeName {
   if (dataType === 'string' || dataType === 'number' || dataType === 'boolean') {
     return dataType;
   }
+  if (dataType === 'object') {
+    return Array.isArray(formData) ? 'array' : 'object';
+  }
   // Treat everything else as a string
   return 'string';
 }
@@ -106,20 +109,14 @@ export default function FallbackField<
   };
 
   if (!globalFormOptions.useFallbackUiForUnsupportedType) {
+    const { reason = translateString(TranslatableString.UnknownFieldType, [String(schema.type)]) } = props;
     const UnsupportedFieldTemplate = getTemplate<'UnsupportedFieldTemplate', T, S, F>(
       'UnsupportedFieldTemplate',
       registry,
       uiOptions,
     );
 
-    return (
-      <UnsupportedFieldTemplate
-        schema={schema}
-        fieldPathId={fieldPathId}
-        reason={translateString(TranslatableString.UnknownFieldType, [String(schema.type)])}
-        registry={registry}
-      />
-    );
+    return <UnsupportedFieldTemplate schema={schema} fieldPathId={fieldPathId} reason={reason} registry={registry} />;
   }
 
   const FallbackFieldTemplate = getTemplate<'FallbackFieldTemplate', T, S, F>(
@@ -151,7 +148,18 @@ export default function FallbackField<
           required={required}
         />
       }
-      schemaField={<SchemaField {...props} schema={{ type, title: translateString(TranslatableString.Value) } as S} />}
+      schemaField={
+        <SchemaField
+          {...props}
+          schema={
+            {
+              type,
+              title: translateString(TranslatableString.Value),
+              ...(type === 'object' && { additionalProperties: true }),
+            } as S
+          }
+        />
+      }
     />
   );
 }

packages/core/src/components/fields/ObjectField.tsx

@@ -1,6 +1,5 @@
 import { FocusEvent, useCallback, useState } from 'react';
 import {
-  ADDITIONAL_PROPERTY_KEY_REMOVE,
   ADDITIONAL_PROPERTY_FLAG,
   ANY_OF_KEY,
   getTemplate,
@@ -30,6 +29,8 @@ import has from 'lodash/has';
 import isObject from 'lodash/isObject';
 import set from 'lodash/set';
 
+import { ADDITIONAL_PROPERTY_KEY_REMOVE } from '../constants';
+
 /** Returns a flag indicating whether the `name` field is required in the object schema
  *
  * @param schema - The schema to check

packages/core/test/Form.test.jsx

@@ -145,6 +145,69 @@ describeRepeated('Form common', (createFormComponent) => {
         },
         'root_unknownProperty',
       );
+
+      // Change the fallback type to 'boolean'
+      fireEvent.change(node.querySelector('select'), { target: { value: 2 } });
+      optionValue = node.querySelector('select').value;
+      optionText = node.querySelector(`select option[value="${optionValue}"]`).textContent;
+      expect(optionText).to.equal('boolean');
+      expect(node.querySelector('input[type=checkbox]')).to.exist;
+      expect(node.querySelector('input[type=checkbox]').checked).to.equal(true);
+      // Verify formData was casted to number
+      sinon.assert.calledWithMatch(
+        onChange.lastCall,
+        {
+          formData: {
+            unknownProperty: true,
+          },
+          schema,
+        },
+        'root_unknownProperty',
+      );
+
+      // Change the fallback type to 'object'
+      fireEvent.change(node.querySelector('select'), { target: { value: 3 } });
+      optionValue = node.querySelector('select').value;
+      optionText = node.querySelector(`select option[value="${optionValue}"]`).textContent;
+      expect(optionText).to.equal('object');
+      let addButton = node.querySelector('.rjsf-object-property-expand button');
+      expect(addButton).to.exist;
+      // click the add button
+      act(() => addButton.click());
+
+      // Verify formData was casted to number
+      sinon.assert.calledWithMatch(
+        onChange.lastCall,
+        {
+          formData: {
+            unknownProperty: { newKey: 'New Value' },
+          },
+          schema,
+        },
+        'root_unknownProperty',
+      );
+
+      // Change the fallback type to 'array'
+      fireEvent.change(node.querySelector('select'), { target: { value: 4 } });
+      optionValue = node.querySelector('select').value;
+      optionText = node.querySelector(`select option[value="${optionValue}"]`).textContent;
+      expect(optionText).to.equal('array');
+      addButton = node.querySelector('.rjsf-array-item-add button');
+      expect(addButton).to.exist;
+      // click the add button
+      act(() => addButton.click());
+
+      // Verify formData was casted to number
+      sinon.assert.calledWithMatch(
+        onChange.lastCall,
+        {
+          formData: {
+            unknownProperty: [undefined],
+          },
+          schema,
+        },
+        'root_unknownProperty',
+      );
     });
   });
 

packages/utils/src/constants.ts

@@ -4,7 +4,6 @@
  * utility.
  */
 export const ADDITIONAL_PROPERTY_FLAG = '__additional_property';
-export const ADDITIONAL_PROPERTY_KEY_REMOVE = Symbol('remove-this-key');
 export const ADDITIONAL_PROPERTIES_KEY = 'additionalProperties';
 export const ALL_OF_KEY = 'allOf';
 export const ANY_OF_KEY = 'anyOf';