This type accepts at least one property

atLeastOne.ts

type AtLeastOnePropertyOf<T, K extends keyof T> = K extends K ? Record<K, T[K]> : never

type User = {
    name: string;
    age: number;
}
type UpdateUser = AtLeastOnePropertyOf<User, keyof User> & Partial<User> 

const user = {
    name: 'name',
    age: 10
};

function updateAtLeastOne(user: User, newUser: UpdateUser) {
}

updateAtLeastOne(user, {
    age: 20
})