Addcartphp Num High Quality -

At its heart, a shopping cart must support a few fundamental operations: adding items, removing items, updating quantities, and calculating totals. Let's examine each function in detail with a focus on high-quality implementation.

Validate that the product_id and quantity are present, numeric, and safe to use. addcartphp num high quality

// For integer quantities (most common case) $qty = (int) $cleanQty; if ((string)$qty !== $cleanQty) // Handle decimal when expecting integer throw new InvalidArgumentException('Only whole numbers allowed.'); At its heart, a shopping cart must support

// Add or update item if (isset($_SESSION['cart'][$cartKey])) // Item exists – accumulate quantity $_SESSION['cart'][$cartKey]['quantity'] += $quantity; $_SESSION['cart'][$cartKey]['quantity'] = min( $_SESSION['cart'][$cartKey]['quantity'], $product['max_order_qty'] ?? 999 ); else // New item – store only essential data $_SESSION['cart'][$cartKey] = [ 'product_id' => $productId, 'quantity' => $quantity, 'variants' => $variants, 'added_at' => time() ]; // For integer quantities (most common case) $qty