Tired of writing classes and functions that do similar things? Frustrated that your dog & cat types aren’t allowed in your filter function. That TS once again complains about types? Try Generics and get a glimpse of the feeling of your beloved untyped language! Let your compiler do the writing!

Testing a react component can be many types of test. If the paradigm of the application is a thick client. Then the component can have a lot of responsibility. I would argue that testing a react component can vary from e2e to unit test dependent on the scope the component is responsible for.

Integrations tests are different from e2e as they typically mock services and they test apis. Also they can be done solely on backend services or solely on some FE components
E2E usually are requirement / user story focused. E2E both assert front- and backend.