Adds an event handler that runs when a product's quantity is changed.
This function is currently only available for Wix Studio sites.
The onQuantityChanged() function adds an event handler that runs when a product's quantity is changed.
quantityChangedEventHandler(quantity: number): void The function to run when a product's quantity is changed.
This method doesn’t return any custom errors, but may return standard errors. Learn more about standard Wix errors.