var health = 16;
var potion = 5;

health = Math.min(20, health + potion)

var itemSelection = prompt("HP: " + playerHp + "nItems:n1.Potion - INFO: Restores 5 HP.  Can attack after use" + "nQTY: " + potions + "n2.Exit");

switch (itemSelection) {
    case '1':
        if(playerHp === 20){
            alert("You are already at full health.");
        }else{
        playerHp += 5;
        potions -= 1;
        if (playerHp > 20) {
            playerHp = 20;
        }
        }
        playerTurn();
        break;
    case '2':
        playerTurn();
        break;
    default:
        alert("Invalid choice.");
        itemMenu();
}