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

Inizia con l’esempio Playground collegato e riproduci l’errore del decorator relativo a keyof, alle classi generiche e a un campo opzionale. Traccia la gestione da parte del compilatore del tipo di destinazione del decorator, quindi aggiungi un test di regressione che includa sia Address sia AddressBroken e verifica che entrambi gli esempi vengano compilati senza l’errore segnalato.