typescript get type based on decorator code example

Example: typescript decorators

tsfunction f() {
  console.log("f(): evaluated");
  return function(target, propertyKey: string, descriptor: PropertyDescriptor) {
    console.log("f(): called");
  };
}

function g() {
  console.log("g(): evaluated");
  return function(target, propertyKey: string, descriptor: PropertyDescriptor) {
    console.log("g(): called");
  };
}

class C {
  @f()
  @g()
  method() {}
}