refactor: convert function expressions to declarations (#4926)

packages/netlify-cms-widget-list/src/ListControl.js

@@ -72,13 +72,13 @@ const valueTypes = {
   MIXED: 'MIXED',
 };
 
-const handleSummary = (summary, entry, label, item) => {
+function handleSummary(summary, entry, label, item) {
   const data = stringTemplate.addFileTemplateFields(
     entry.get('path'),
     item.set('fields.label', label),
   );
   return stringTemplate.compileStringTemplate(summary, null, '', data);
-};
+}
 
 export default class ListControl extends React.Component {
   validations = [];

packages/netlify-cms-widget-list/src/__tests__/ListControl.spec.js

@@ -18,12 +18,16 @@ jest.mock('netlify-cms-widget-object', () => {
 });
 jest.mock('netlify-cms-ui-default', () => {
   const actual = jest.requireActual('netlify-cms-ui-default');
-  const ListItemTopBar = props => (
-    <mock-list-item-top-bar {...props} onClick={props.onCollapseToggle}>
-      <button onClick={props.onRemove}>Remove</button>
-      {props.children}
-    </mock-list-item-top-bar>
-  );
+
+  function ListItemTopBar(props) {
+    return (
+      <mock-list-item-top-bar {...props} onClick={props.onCollapseToggle}>
+        <button onClick={props.onRemove}>Remove</button>
+        {props.children}
+      </mock-list-item-top-bar>
+    );
+  }
+
   return {
     ...actual,
     ListItemTopBar,

packages/netlify-cms-widget-list/src/index.js

@@ -3,13 +3,16 @@ import NetlifyCmsWidgetObject from 'netlify-cms-widget-object';
 import schema from './schema';
 
 const previewComponent = NetlifyCmsWidgetObject.previewComponent;
-const Widget = (opts = {}) => ({
-  name: 'list',
-  controlComponent,
-  previewComponent,
-  schema,
-  ...opts,
-});
+
+function Widget(opts = {}) {
+  return {
+    name: 'list',
+    controlComponent,
+    previewComponent,
+    schema,
+    ...opts,
+  };
+}
 
 export const NetlifyCmsWidgetList = { Widget, controlComponent, previewComponent };
 export default NetlifyCmsWidgetList;