Spot the bug - #174: Cart Coupon Evaluator

programming web dev
1

Why is this checkout coupon always triggering the default tier?

function resolveDiscountTier(subtotal, promoCode) {
  let tier = 'STANDARD';
  const isVip = promoCode === 'VIP_HERO';

  switch (subtotal) {
    case subtotal >= 100 && isVip:
      tier = 'PLATINUM';
      break;
    case subtotal >= 100:
      tier = 'GOLD';
      break;
    case subtotal >= 50:
      tier = 'SILVER';
      break;
    default:
      tier = 'BRONZE';
  }
  return tier;
}

Reply with what is broken and how you would fix it.