You explained TDD very easily. I enjoyed watching it because you explained the concept of TDD very easily. Your source code style seems similar to React or Vue. I have a question. In a project that cannot use ES6 yet, you will need to convert it to ES5 and distribute it. Can you guarantee that the code tested in ES6 will pass the test even after converting it to ES5? Thank you for the great lecture. I will watch other lectures as well!