JuniorTheoryCommon

On which line does tsc report an error?

TypeScript

type Order = { readonly id: number; total: number };
const o: Order = { id: 1, total: 50 };
o.total = 60;
o.id = 2;
console.log(o.id, o.total);

Expecting readonly to forbid setting id in the literal too: the value is given when the object is created, and only later writes are errors.
Expecting const o to freeze every property: const only keeps another object out of o, so o.total = 60 is allowed.

Does readonly stop the write on line 4 when the compiled JavaScript runs?
How would you make total read-only as well, and what would tsc then report about line 3?

JuniorTheoryCommon

TypeScript

type Order = { readonly id: number; total: number };
const o: Order = { id: 1, total: 50 };
o.total = 60;
o.id = 2;
console.log(o.id, o.total);

Expecting readonly to forbid setting id in the literal too: the value is given when the object is created, and only later writes are errors.
Expecting const o to freeze every property: const only keeps another object out of o, so o.total = 60 is allowed.

Does readonly stop the write on line 4 when the compiled JavaScript runs?
How would you make total read-only as well, and what would tsc then report about line 3?