refactor: move FlagIconFactory to separate file

Author: matteocng

src/js/CustomFlag.js

@@ -1,19 +1,11 @@
 // @flow
-import React from 'react'
-import FlagIconFactory from 'react-flag-icon-css'
-
+import * as React from 'react'
+import type { Node } from 'react';
+import FlagIcon from './FlagIcon';
 import { pick } from './functions'
 import type { CustomFlagPropsType } from '../types/flow'
 
-import { styles, codes } from '../meta-flags-css'
-
-const FlagIcon = FlagIconFactory(React, {
-  useCssModules: __USE_CSS_MODULES__,
-  themeStyles: styles,
-  customCodes: codes,
-})
-
-export default ({ ...props, children }: CustomFlagPropsType): React$Element<*> => {
+export default ({ ...props, children }: CustomFlagPropsType): Node => {
   const { className } = props
   const flagIconProps = pick(props, ['code', 'size', 'flip', 'rotate', 'squared', 'Component'])
 

src/js/FlagIcon.js

@@ -0,0 +1,12 @@
+// @flow
+import React from 'react';
+import FlagIconFactory from 'react-flag-icon-css'
+import { styles, codes } from '../meta-flags-css'
+
+const FlagIcon = FlagIconFactory(React, {
+  useCssModules: __USE_CSS_MODULES__,
+  themeStyles: styles,
+  customCodes: codes,
+})
+
+export default FlagIcon;