Nested Copies

Nested data needs a copy at each level that changes.

nested.ts

type Address = {
    city: string;
    country: string;
};

type Profile = {
    name: string;
    address: Address;
};

const nextCity: string = ;
const profile: Profile = {
    name: "Ada",
    address: { city: "London", country: "UK" },
};

const moved: Profile = {
    ...profile,
    address: { ...profile.address, city: nextCity },
};

console.log(`before=${profile.address.city}`);
console.log(`after=${moved.address.city}`);

type Address = {
    city: string;
    country: string;
};

type Profile = {
    name: string;
    address: Address;
};

const nextCity: string = ;
const profile: Profile = {
    name: "Ada",
    address: { city: "London", country: "UK" },
};

const moved: Profile = {
    ...profile,
    address: { ...profile.address, city: nextCity },
};

console.log(`before=${profile.address.city}`);
console.log(`after=${moved.address.city}`);

type Address = {
    city: string;
    country: string;
};

type Profile = {
    name: string;
    address: Address;
};

const nextCity: string = ;
const profile: Profile = {
    name: "Ada",
    address: { city: "London", country: "UK" },
};

const moved: Profile = {
    ...profile,
    address: { ...profile.address, city: nextCity },
};

console.log(`before=${profile.address.city}`);
console.log(`after=${moved.address.city}`);

nested copy When a nested object changes, copy the outer object and the inner object so unchanged references stay separate from updated data.