I am learning type script and came across two different ways of declaring methods.
I am wondering what is the difference between the below two different function declaration g and f in type script. Both functions don’t return any value. Is one more preferred over the other?

interface A {
  g(): void;
  f: () => void;
}
class AImpl implements A {
  g(): void {
    console.log("Hello");
  }
  constructor() {
    this.f = this.g;
  }
  f: () => void;
}

I have tried to find something on internet, specifically stack overflow but couldn’t.
I don’t quite understand the difference in syntax.