Optional fields affecting keyof operator in generic class decorators

TypeScript Version: 3.2.2

Search Terms:
class decorator keyof typescript

Code

function View<T>(name: string, fields: (keyof T)[]) {
  return (target: new(...args: any[]) => T) => {
    // Do something with fields
  };
}

// works
@View('active', ['street1', 'street2'])
class Address {
  street1: string;
  street2: string;
}

// broken
@View('active', ['street1', 'street2'])
class AddressBroken {
  street1: string;
  street2?: string;
}

Expected behavior:
Both scenarios should work above.

Actual behavior:
It appears that optional fields are causing the decorator to create invalid types.

Argument of type 'typeof AddressBroken' is not assignable to parameter of type 'new (...args: any[]) => { street1: any; street2: any; }'.
  Type 'AddressBroken' is not assignable to type '{ street1: any; street2: any; }'.
    Property 'street2' is optional in type 'AddressBroken' but required in type '{ street1: any; street2: any; }'.
1234

Playground Link:
Playground Sample

Commencez par l’exemple Playground lié et reproduisez l’erreur de décorateur impliquant keyof, les classes génériques et un champ optionnel. Suivez le traitement par le compilateur du type cible du décorateur, puis ajoutez un test de régression couvrant à la fois Address et AddressBroken et vérifiez que les deux exemples sont compilés sans l’erreur signalée.