[Typescript] “Partial” Mapped Type

type MyPartial<T> = {
    [P in keyof T]?: T[P]
}

'in' like a loop. 

Usage:

function updatePerson(person: Person, prop: MyPartial<Person>) {
    return {...person, ...prop}
}

or built-in:

function updatePerson(person: Person, prop: Partial<Person>) {
    return {...person, ...prop}
}