fix: create FlagIcon one time onlygit add src/js/CustomFlag.js

Author: matteocng

src/js/CustomFlag.js

@@ -5,11 +5,15 @@ import FlagIconFactory from 'react-flag-icon-css'
 import { pick } from './functions'
 import type { CustomFlagPropsType } from '../types/flow'
 
-import themeStyles from '../meta-flags-css'
+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<*> => {
-  const FlagIcon = FlagIconFactory(React, { useCssModules: __USE_CSS_MODULES__, themeStyles })
   const { className } = props
   const flagIconProps = pick(props, ['code', 'size', 'flip', 'rotate', 'squared', 'Component'])