Objects.

Fifth class. A bare amount lacks context. An object groups named fields:

const item = { category: "food", amount: 12 };

Read with item.category, item.amount. Curly braces {} create the object. Keys are identifiers (or strings).

Mini example:

const bill = { category: "rent", amount: 40 }; console.log(bill.category);

Common mistake: using = instead of : inside the literal; or looking up item["Food"] with the wrong capital letter.