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Stdle #146 · classes · 2026-10-30

What does this TypeScript snippet output?

A past puzzle — fully playable. 4 attempts, hints on wrong guesses.

class Base { fmt(...n: number[]) { return n.length; } }
class Sub extends Base { fmt(a: number, b: number) { return a + b; } }
const x: Base = new Sub();
console.log(x.fmt(3, 4));
Classes
4 attempts left

Answer & explanation