fix: rjsf-team#2768 by returning id on the Form.onChange handler

- In @rjsf/utils, updated the `FieldProps` type for `onChange` to add an optional `id: string` parameter, making `onChange` for `FieldTemplateProps` use `FieldProps` definition
- In @rjsf/core, updated the library to support returning an optional second parameter, `id: string`, to the `onChange()` prop on `Form` as follows:
  - Updated the `Form.onChange()` callback handler passed to all fields to take an optional third parameter, `id: string`, passing it out to the `onChange()` prop call
  - Updated `ArrayField` to make the callback returned from the `onChangeForIndex()` method take the additional `id` parameter and pass it along to the `props.onChange()` handler
  - Updated `MultiSchemaField` to make the `onOptionChange()` method pass along the `this.getFieldId()` value to the `props.onChange()` handler
    - Refactored the `id` logic for the select widget used in the `MultiSchemaField` into the `getFieldId()` method
  - Updated `ObjectField` to make the callback returned from the `onPropertyChange()` method take the additional `id` parameter and pass it along to the `props.onChange()` handler
  - Updated `SchemaField` to add a new `handleFieldComponentChange()` callback that ensures that an `id` is passed up the `onChange` callback chain
    - Updated the render of the `FieldComponent` to pass the `handleFieldComponentChange()` as the `onChange` handler
  - Updated all of the tests to check for the `id` in those situations when it is passed back
- In @rjsf/playground, updated the `onFormDataChange` handler to log the `id` of the changed field if it is provided
- Updated the `form-props.md` documentation to describe the new `id` parameter that may be returned
- Updated the `CHANGELOG.md` accordingly

CHANGELOG.md

@@ -17,8 +17,16 @@ should change the heading of the (upcoming) version to include a major version b
 -->
 # 5.0.0-beta.11
 
-## @rjsf/playground
+## @rjsf/core
+- Extended `Form.onChange` to optionally return the `id` of the field that caused the change, fixing (https://github.com/rjsf-team/react-jsonschema-form/issues/2768)
+
+## @rjsf/utils
+- Updated the `onChange` prop on `FieldProps` and `FieldTemplateProps` to add an optional `id` parameter to the callback.
+
+## Dev / docs / playground
 - Added an error boundary to prevent the entire app from crashing when an error is thrown by Form. See [#3164](https://github.com/rjsf-team/react-jsonschema-form/pull/3164) for closed issues.
+- Updated the playground to log the `id` of the field being changed on the `onChange` handler
+- Updated `form-props.md` file to describe the new `id` parameter being returned by the `Form.onChange` handler
 
 # 5.0.0-beta.10
 

docs/api-reference/form-props.md

@@ -193,7 +193,10 @@ Sometimes you may want to trigger events or modify external state when a field h
 
 ## onChange
 
-If you plan on being notified every time the form data are updated, you can pass an `onChange` handler, which will receive the same args as `onSubmit` any time a value is updated in the form.
+If you plan on being notified every time the form data are updated, you can pass an `onChange` handler, which will receive the same first argument as `onSubmit` any time a value is updated in the form.
+It will also receive, as the second argument, the `id` of the field which experienced the change.
+Generally, this will be the `id` of the field for which input data is modified.
+In the case of adding/removing of new fields in arrays or objects with `additionalProperties` and the rearranging of items in arrays, the `id` will be that of the array or object itself, rather than the item/field being added, removed or moved.
 
 ## onError
 
@@ -218,7 +221,9 @@ Sometimes you may want to trigger events or modify external state when a field h
 
 ## onSubmit
 
-You can pass a function as the `onSubmit` prop of your `Form` component to listen to when the form is submitted and its data are valid. It will be passed a result object having a `formData` attribute, which is the valid form data you're usually after. The original event will also be passed as a second parameter:
+You can pass a function as the `onSubmit` prop of your `Form` component to listen to when the form is submitted and its data are valid.
+It will be passed a result object having a `formData` attribute, which is the valid form data you're usually after.
+The original event will also be passed as a second parameter:
 
 ```jsx
 import validator from "@rjsf/validator-ajv6";

packages/core/src/components/Form.tsx

@@ -80,9 +80,10 @@ export interface FormProps<T = any, F = any> {
   widgets?: RegistryWidgetsType<T, F>;
   // Callbacks
   /** If you plan on being notified every time the form data are updated, you can pass an `onChange` handler, which will
-   * receive the same args as `onSubmit` any time a value is updated in the form
+   * receive the same args as `onSubmit` any time a value is updated in the form. Can also return the `id` of the field
+   * that caused the change
    */
-  onChange?: (data: IChangeEvent<T, F>) => void;
+  onChange?: (data: IChangeEvent<T, F>, id?: string) => void;
   /** To react when submitted form data are invalid, pass an `onError` handler. It will be passed the list of
    * encountered errors
    */
@@ -503,8 +504,9 @@ export default class Form<T = any, F = any> extends Component<
    *
    * @param formData - The new form data from a change to a field
    * @param newErrorSchema - The new `ErrorSchema` based on the field change
+   * @param id - The id of the field that caused the change
    */
-  onChange = (formData: T, newErrorSchema?: ErrorSchema<T>) => {
+  onChange = (formData: T, newErrorSchema?: ErrorSchema<T>, id?: string) => {
     const {
       extraErrors,
       omitExtraData,
@@ -572,7 +574,7 @@ export default class Form<T = any, F = any> extends Component<
     }
     this.setState(
       state as FormState<T, F>,
-      () => onChange && onChange({ ...this.state, ...state })
+      () => onChange && onChange({ ...this.state, ...state }, id)
     );
   };
 

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

@@ -344,7 +344,7 @@ class ArrayField<T = any, F = any> extends Component<
    * @param index - The index of the item being changed
    */
   onChangeForIndex = (index: number) => {
-    return (value: any, newErrorSchema?: ErrorSchema<T>) => {
+    return (value: any, newErrorSchema?: ErrorSchema<T>, id?: string) => {
       const { formData, onChange, errorSchema } = this.props;
       const arrayData = Array.isArray(formData) ? formData : [];
       const newFormData = arrayData.map((item: T, i: number) => {
@@ -359,15 +359,16 @@ class ArrayField<T = any, F = any> extends Component<
           errorSchema && {
             ...errorSchema,
             [index]: newErrorSchema,
-          }
+          },
+        id
       );
     };
   };
 
   /** Callback handler used to change the value for a checkbox */
   onSelectChange = (value: any) => {
-    const { onChange } = this.props;
-    onChange(value);
+    const { onChange, idSchema } = this.props;
+    onChange(value, undefined, idSchema && idSchema.$id);
   };
 
   /** Renders the `ArrayField` depending on the specific needs of the schema and uischema elements

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

@@ -132,14 +132,26 @@ class AnyOfField<T = any, F = any> extends Component<
     }
     // Call getDefaultFormState to make sure defaults are populated on change.
     onChange(
-      schemaUtils.getDefaultFormState(options[selectedOption], newFormData) as T
+      schemaUtils.getDefaultFormState(
+        options[selectedOption],
+        newFormData
+      ) as T,
+      undefined,
+      this.getFieldId()
     );
 
     this.setState({
       selectedOption: parseInt(option, 10),
     });
   };
 
+  getFieldId() {
+    const { idSchema, schema } = this.props;
+    return `${idSchema.$id}${
+      schema.oneOf ? "__oneof_select" : "__anyof_select"
+    }`;
+  }
+
   /** Renders the `AnyOfField` selector along with a `SchemaField` for the value of the `formData`
    */
   render() {
@@ -161,7 +173,6 @@ class AnyOfField<T = any, F = any> extends Component<
       options,
       registry,
       uiSchema,
-      schema,
     } = this.props;
 
     const { widgets, fields } = registry;
@@ -190,9 +201,7 @@ class AnyOfField<T = any, F = any> extends Component<
       <div className="panel panel-default panel-body">
         <div className="form-group">
           <Widget
-            id={`${idSchema.$id}${
-              schema.oneOf ? "__oneof_select" : "__anyof_select"
-            }`}
+            id={this.getFieldId()}
             schema={{ type: "number", default: 0 }}
             onChange={this.onOptionChange}
             onBlur={onBlur}

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

@@ -62,7 +62,7 @@ class ObjectField<T = any, F = any> extends Component<
    * @returns - The onPropertyChange callback for the `name` property
    */
   onPropertyChange = (name: string, addedByAdditionalProperties = false) => {
-    return (value: T, newErrorSchema?: ErrorSchema<T>) => {
+    return (value: T, newErrorSchema?: ErrorSchema<T>, id?: string) => {
       const { formData, onChange, errorSchema } = this.props;
       if (value === undefined && addedByAdditionalProperties) {
         // Don't set value = undefined for fields added by
@@ -81,7 +81,8 @@ class ObjectField<T = any, F = any> extends Component<
           errorSchema && {
             ...errorSchema,
             [name]: newErrorSchema,
-          }
+          },
+        id
       );
     };
   };

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

@@ -5,6 +5,7 @@ import {
   getUiOptions,
   getSchemaType,
   getTemplate,
+  ErrorSchema,
   FieldProps,
   FieldTemplateProps,
   IdSchema,
@@ -132,16 +133,23 @@ function SchemaFieldRender<T, F>(props: FieldProps<T, F>) {
     uiOptions
   );
   const schema = schemaUtils.retrieveSchema(_schema, formData);
+  const fieldId = _idSchema[ID_KEY];
   const idSchema = mergeObjects(
-    schemaUtils.toIdSchema(
-      schema,
-      _idSchema.$id,
-      formData,
-      idPrefix,
-      idSeparator
-    ),
+    schemaUtils.toIdSchema(schema, fieldId, formData, idPrefix, idSeparator),
     _idSchema
   ) as IdSchema<T>;
+
+  /** Intermediary `onChange` handler for field components that will inject the `id` of the current field into the
+   * `onChange` chain if it is not already being provided from a deeper level in the hierarchy
+   */
+  const handleFieldComponentChange = React.useCallback(
+    (formData: T, newErrorSchema?: ErrorSchema<T>, id?: string) => {
+      const theId = id || fieldId;
+      return onChange(formData, newErrorSchema, theId);
+    },
+    [fieldId, onChange]
+  );
+
   const FieldComponent = getFieldComponent(
     schema,
     uiOptions,
@@ -180,6 +188,7 @@ function SchemaFieldRender<T, F>(props: FieldProps<T, F>) {
   const field = (
     <FieldComponent
       {...props}
+      onChange={handleFieldComponentChange}
       idSchema={idSchema}
       schema={schema}
       uiSchema={fieldUiSchema}