Why does codepen thrown an error when I try to run this javascript?

It doesn’t throw there error unless I get into the last else statement.

https://codepen.io/bnjwin/pen/YzbQOzo

    else {
    let result ="";
    for (const [symbol, number] of numerals) {
      while (input >= number) {
        result += symbol;
        input -= number;
      }
    }
    output.innerText = result;
  }

I built this code on freecodecamp.org and it works there.

I was expecting it to work on codepen.