where does vscode store types for typescript code example

Example 1: doest all the methos in interface need to implement c#

You have two choices:

- implement every method required by the interface
or
- declare the missing methods abstract in your class. This forces you
to declare your class abstract and, as a result, forces you to
subclass the class (and implement the missing methods) before you
can create any objects.

Example 2: why can't define generic function in tsx file

const f = <T1, _>(arg1: T1) => {
   return { arg1 };
};

// or just adding a comma
const g = <T1,>(arg1: T1) => {
   return { arg1 };
};