typescript
1interface Address {
2  street: string;
3  city: string;
4}
5
6interface Customer {
7  name: string;
8  address: Address; // Nested object
9}
10
11const original: Customer = {
12  name: 'John',
13  address: { street: '123 Main', city: 'NYC' }
14};
15
16// Shallow copy - address is shared!
17const shallow = { ...original };
18shallow.address.street = '456 Oak';
19console.log(original.address.street); // '456 Oak' - MODIFIED!