type Optional <T extends {}, O extends keyof T> = any
 
type Person = {name: string, age:number; phone: number}
type OptionalAge = Optional<Person, 'age'> // {name:string, age?:number, phone:number}
type OptionalAgePhone = Optional<Person, 'age'| 'phone'> // {name:string; age?:number;phone?:number }