Improve code quality and write tests

node_modules/@babel/helper-module-transforms/lib/rewrite-this.js

@@ -0,0 +1,29 @@
+"use strict";
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+exports.default = rewriteThis;
+
+function rewriteThis(programPath) {
+  programPath.traverse(rewriteThisVisitor);
+}
+
+const rewriteThisVisitor = {
+  ThisExpression(path) {
+    path.replaceWith(path.scope.buildUndefinedNode());
+  },
+
+  Function(path) {
+    if (!path.isArrowFunctionExpression()) path.skip();
+  },
+
+  ClassProperty(path) {
+    path.skip();
+  },
+
+  ClassPrivateProperty(path) {
+    path.skip();
+  }
+
+};