JuniorTheoryCommon

What does the program print?

JavaScript

const o = { b: 1, 2: 1, a: 1, 1: 1 };
console.log(Object.keys(o).join(" "));

1 2 b a

Expecting b 2 a 1, the order the keys were written in: integer-like keys such as 2 and 1 always come first, in ascending order.
Expecting 1 2 a b: only the integer-like keys are sorted; the other keys keep the order they were added in, so b stays before a.

JuniorTheoryCommon

JavaScript

const o = { b: 1, 2: 1, a: 1, 1: 1 };
console.log(Object.keys(o).join(" "));

1 2 b a

Expecting b 2 a 1, the order the keys were written in: integer-like keys such as 2 and 1 always come first, in ascending order.
Expecting 1 2 a b: only the integer-like keys are sorted; the other keys keep the order they were added in, so b stays before a.