Any hands on tutorial to learn common test procedure of Javascript

All:

I am pretty new to testing. I wonder if anyone can show me some good tutorial about JS TDD/BDD (my chosen stack is React.js and Jasmine), I kinda understanding how to use them theoretically, but when it comes to real development, I get lost about WHAT to test and HOW to test, any suggestion?

Could anyone just use the example of developing a todo list as one example(which allows add edit delete todo item), show what entire testing procedure should be?

Thanks