[Form lib] Add "updateFieldValues" to the form hook API

src/plugins/es_ui_shared/static/forms/components/fields/combobox_field.tsx

@@ -42,7 +42,8 @@ export const ComboBoxField = ({ field, euiFieldProps = {}, idAria, ...rest }: Pr
 
   const onCreateComboOption = (value: string) => {
     // Note: for now, all validations for a comboBox array item have to be synchronous
-    // If there is a need to support asynchronous validation, we'll work on it (and will need to update the <EuiComboBox /> logic).
+    // If there is a need to support asynchronous validation, we'll need to update this handler and
+    // make the <EuiComboBox /> "onCreateOption" handler async).
     const { isValid } = field.validate({
       value,
       validationType: VALIDATION_TYPES.ARRAY_ITEM,
@@ -84,7 +85,7 @@ export const ComboBoxField = ({ field, euiFieldProps = {}, idAria, ...rest }: Pr
         placeholder={i18n.translate('esUi.forms.comboBoxField.placeHolderText', {
           defaultMessage: 'Type and then hit "ENTER"',
         })}
-        selectedOptions={(field.value as any[]).map((v) => ({ label: v }))}
+        selectedOptions={(field.value as string[]).map((v) => ({ label: v }))}
         onCreateOption={onCreateComboOption}
         onChange={onComboChange}
         onSearchChange={onSearchComboChange}

src/plugins/es_ui_shared/static/forms/docs/core/form_hook.mdx

@@ -212,3 +212,22 @@ Sets field errors imperatively.
 ```js
 form.setFieldErrors('name', [{ message: 'There is an error in the field' }]);
 ```
+
+### updateFieldValues()
+
+**Arguments:** `updatedFormData: Partial<T>, options?: { runDeserializer?: boolean }` 
+
+Update multiple field values at once. You don't need to provide all the form fields, **partial** update is supported. This method is mainly useful to update an array of object fields or to avoid multiple `form.setFieldValue()` calls.
+
+```js
+// Update an array of object (e.g "myArray[0].foo", "myArray[0].baz"...)
+form.updateFieldValues({
+  myArray: [
+    { foo: 'bar', baz: true },
+    { foo2: 'bar2', baz: false }
+  ]
+});
+
+// or simply multiple fields at once
+form.updateFieldValues({ foo: 'bar', baz: false })
+```

src/plugins/es_ui_shared/static/forms/hook_form_lib/components/use_array.test.tsx

@@ -77,11 +77,7 @@ describe('<UseArray />', () => {
                 <>
                   {items.map(({ id, path }) => {
                     return (
-                      <UseField
-                        key={id}
-                        path={`${path}.name`}
-                        data-test-subj={`nameField__${id}`}
-                      />
+                      <UseField key={id} path={`${path}.name`} data-test-subj={`${path}Name`} />
                     );
                   })}
                 </>
@@ -102,7 +98,7 @@ describe('<UseArray />', () => {
     } = setup();
 
     await act(async () => {
-      setInputValue('nameField__0', 'John');
+      setInputValue('users[0]Name', 'John');
     });
 
     const formData = onFormData.mock.calls[onFormData.mock.calls.length - 1][0];

src/plugins/es_ui_shared/static/forms/hook_form_lib/components/use_array.ts

@@ -6,7 +6,6 @@
  * Side Public License, v 1.
  */
 
-import uuid from 'uuid';
 import { useEffect, useRef, useCallback, useMemo } from 'react';
 
 import { FormHook, FieldConfig } from '../types';
@@ -37,6 +36,25 @@ export interface FormArrayField {
   form: FormHook;
 }
 
+let uniqueId = 0;
+
+export const createArrayItem = (path: string, index: number, isNew = true): ArrayItem => ({
+  id: uniqueId++,
+  path: `${path}[${index}]`,
+  isNew,
+});
+
+/**
+ * We create an internal field to represent the Array items. This field is not returned
+ * as part as the form data but is used internally to run validation on the array items.
+ * It is this internal field value (ArrayItem[]) that we then map to actual form fields
+ * (in the children func <UseArray>{({ items }) => (...)}</UseArray>)
+ *
+ * @param path The array path in the form data
+ * @returns The internal array field path
+ */
+export const getInternalArrayFieldPath = (path: string): string => `${path}__array__`;
+
 /**
  * Use UseArray to dynamically add fields to your form.
  *
@@ -60,41 +78,26 @@ export const UseArray = ({
   children,
 }: Props) => {
   const isMounted = useRef(false);
-  const uniqueId = useRef(0);
 
   const form = useFormContext();
   const { getFieldDefaultValue } = form;
 
-  const getNewItemAtIndex = useCallback(
-    (index: number): ArrayItem => ({
-      id: uniqueId.current++,
-      path: `${path}[${index}]`,
-      isNew: true,
-    }),
-    [path]
-  );
-
   const fieldDefaultValue = useMemo<ArrayItem[]>(() => {
     const defaultValues = readDefaultValueOnForm
       ? getFieldDefaultValue<unknown[]>(path)
       : undefined;
 
     if (defaultValues) {
-      return defaultValues.map((_, index) => ({
-        id: uniqueId.current++,
-        path: `${path}[${index}]`,
-        isNew: false,
-      }));
+      return defaultValues.map((_, index) => createArrayItem(path, index, false));
     }
 
-    return new Array(initialNumberOfItems).fill('').map((_, i) => getNewItemAtIndex(i));
-  }, [path, initialNumberOfItems, readDefaultValueOnForm, getFieldDefaultValue, getNewItemAtIndex]);
+    return new Array(initialNumberOfItems).fill('').map((_, i) => createArrayItem(path, i));
+  }, [path, initialNumberOfItems, readDefaultValueOnForm, getFieldDefaultValue]);
 
   // Create an internal hook field which behaves like any other form field except that it is not
   // outputed in the form data (when calling form.submit() or form.getFormData())
   // This allow us to run custom validations (passed to the props) on the Array items
-
-  const internalFieldPath = useMemo(() => `${path}__${uuid.v4()}`, [path]);
+  const internalFieldPath = useMemo(() => getInternalArrayFieldPath(path), [path]);
 
   const fieldConfigBase: FieldConfig<ArrayItem[]> & InternalFieldConfig<ArrayItem[]> = {
     defaultValue: fieldDefaultValue,
@@ -132,9 +135,9 @@ export const UseArray = ({
   const addItem = useCallback(() => {
     setValue((previousItems) => {
       const itemIndex = previousItems.length;
-      return [...previousItems, getNewItemAtIndex(itemIndex)];
+      return [...previousItems, createArrayItem(path, itemIndex)];
     });
-  }, [setValue, getNewItemAtIndex]);
+  }, [setValue, path]);
 
   const removeItem = useCallback(
     (id: number) => {