refactor: extract DefaultLabelFn

packages/ra-ui-materialui/src/form/SimpleFormIterator.tsx

@@ -1,27 +1,26 @@
+import Button from '@material-ui/core/Button';
+import FormHelperText from '@material-ui/core/FormHelperText';
+import { makeStyles } from '@material-ui/core/styles';
+import Typography from '@material-ui/core/Typography';
+import AddIcon from '@material-ui/icons/AddCircleOutline';
+import CloseIcon from '@material-ui/icons/RemoveCircleOutline';
+import classNames from 'classnames';
+import get from 'lodash/get';
+import PropTypes from 'prop-types';
+import { Record, useTranslate, ValidationError } from 'ra-core';
 import * as React from 'react';
 import {
     Children,
     cloneElement,
+    FC,
     isValidElement,
-    useRef,
     ReactElement,
-    FC,
+    useRef,
 } from 'react';
-import PropTypes from 'prop-types';
-import { CSSTransition, TransitionGroup } from 'react-transition-group';
-import get from 'lodash/get';
-import Typography from '@material-ui/core/Typography';
-import Button from '@material-ui/core/Button';
-import FormHelperText from '@material-ui/core/FormHelperText';
-import { makeStyles } from '@material-ui/core/styles';
-import CloseIcon from '@material-ui/icons/RemoveCircleOutline';
-import AddIcon from '@material-ui/icons/AddCircleOutline';
-import { useTranslate, ValidationError, Record } from 'ra-core';
-import classNames from 'classnames';
 import { FieldArrayRenderProps } from 'react-final-form-arrays';
-
-import FormInput from './FormInput';
+import { CSSTransition, TransitionGroup } from 'react-transition-group';
 import { ClassesOverride } from '../types';
+import FormInput from './FormInput';
 
 const useStyles = makeStyles(
     theme => ({
@@ -83,6 +82,8 @@ const DefaultAddButton = props => {
     );
 };
 
+const DefaultLabelFn = index => index + 1;
+
 const DefaultRemoveButton = props => {
     const classes = useStyles(props);
     const translate = useTranslate();
@@ -113,7 +114,7 @@ const SimpleFormIterator: FC<SimpleFormIteratorProps> = props => {
         margin,
         TransitionProps,
         defaultValue,
-        labelFn = index => index + 1,
+        labelFn = DefaultLabelFn,
     } = props;
     const classes = useStyles(props);
     const nodeRef = useRef(null);