JuniorTheoryCommon

What does the program print?

JavaScript

const a = [1, 2];
const r = a.push(7);

console.log(r, a.length);

3 3

Expecting push to return the added element 7: it returns the new length of the array, which is 3.
Expecting TypeError because a is a const: const only forbids assigning a new value to a; the array itself can still change.