refactor: monorepo setup with lerna (#243)

packages/core/test/fileTransformer.js

@@ -0,0 +1,9 @@
+const path = require('path');
+
+module.exports = {
+  process(src, filename) {
+    return {
+      code: `module.exports = ${JSON.stringify(path.basename(filename))};`,
+    };
+  },
+};