Add @react-native/babel-plugin-codegen to the preset if src is null (#…

…39159)

Summary:
X-link: facebook/metro#1078

Pull Request resolved: #39159

Source is not required for `getPreset` of `react-native/babel-preset`. There is a codition that adds `react-native/babel-plugin-codegen` to the preset only if source is passing certain regex. This condition fails if source is null, but that's wrong because the plugin may still be requred for this transformation even though source is not provided.
This diff changes the condition so the regexp tests source only if it is not null, and `react-native/babel-plugin-codegen` automatically added to the preset otherwise.
Changelog: [Internal]

Reviewed By: robhogan

Differential Revision: D48684443

fbshipit-source-id: 7cea69c91c0175ac0374d72e91f58e20fe75fd53

packages/react-native-babel-preset/src/configs/main.js

@@ -57,7 +57,7 @@ const getPreset = (src, options) => {
 
   if (
     !options.disableStaticViewConfigsCodegen &&
-    /\bcodegenNativeComponent</.test(src)
+    (src === null || /\bcodegenNativeComponent</.test(src))
   ) {
     extraPlugins.push([require('@react-native/babel-plugin-codegen')]);
   }