refactor: convert function expressions to declarations (#4926)

packages/netlify-cms-widget-boolean/src/BooleanControl.js

@@ -4,14 +4,16 @@ import ImmutablePropTypes from 'react-immutable-proptypes';
 import { css } from '@emotion/core';
 import { Toggle, ToggleBackground, colors } from 'netlify-cms-ui-default';
 
-const BooleanBackground = ({ isActive, ...props }) => (
-  <ToggleBackground
-    css={css`
-      background-color: ${isActive ? colors.active : colors.textFieldBorder};
-    `}
-    {...props}
-  />
-);
+function BooleanBackground({ isActive, ...props }) {
+  return (
+    <ToggleBackground
+      css={css`
+        background-color: ${isActive ? colors.active : colors.textFieldBorder};
+      `}
+      {...props}
+    />
+  );
+}
 
 export default class BooleanControl extends React.Component {
   render() {

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

@@ -1,10 +1,12 @@
 import controlComponent from './BooleanControl';
 
-const Widget = (opts = {}) => ({
-  name: 'boolean',
-  controlComponent,
-  ...opts,
-});
+function Widget(opts = {}) {
+  return {
+    name: 'boolean',
+    controlComponent,
+    ...opts,
+  };
+}
 
 export const NetlifyCmsWidgetBoolean = { Widget, controlComponent };
 export default NetlifyCmsWidgetBoolean;