add some babel stuff

node_modules/@babel/helper-split-export-declaration/README.md

@@ -0,0 +1,23 @@
+# @babel/helper-split-export-declaration
+
+## API
+
+```js
+declare export default splitExportDeclaration(path: NodePath);
+```
+
+## Usage
+
+```js
+import traverse from "@babel/traverse";
+import splitExportDeclaration from "@babel/helper-split-export-declaration";
+
+// ...
+
+traverse(file, {
+  ExportDefaultDeclaration(path) {
+    if (!path.get("declaration").isClassDeclaration()) return;
+    splitExportDeclaration(path);
+  },
+});
+```