Javascript 轮盘赌问题

我有一个很简单的问题，让我有点发疯。我正在用JavaScript构建一个简单的轮盘赌模拟器。在模拟器的开始，我希望玩家开始时有一个固定的金额--500美元，所以我做了一个变量，其中wallet=500。 一旦玩家下注于红色或黑色，wallet变量将更新为新数量，并由walletWeight（）函数打印。这一切似乎都工作时，播放一次，然而，当播放多次的变量总是恢复到500！ 有人能帮忙吗

完整代码如下：

function BlackOrRed()
{
wallet = 500
function walletWeight(){
  return `You now have $${wallet} in your wallet.`}  
var Red = []
var Black = []
for (i=1; i<37; i++){
  if (i%2===0){
Red.push(i)}
  else {
Black.push(i)}
  }

var gamble = 
prompt("Pick a colour: Black or Red!")
var testing = 0;
while (testing == 0)
{
if(gamble === "Red" || gamble === "Black"|| gamble === "red"|| gamble === "black")
{
    testing = 1;
}
    else
{
    gamble = prompt("Pick a colour: Black or Red!")
    }
  gamble = gamble.toUpperCase() 
}

console.log(`I pick ${gamble}!`)

var bet = 
prompt("How much do you want to bet on that?")

var spin = (Math.floor(Math.random() * 36) + 1)

if (Red.includes(spin)){
  console.log(`${spin}, Red!`)
}
else {
  console.log(`${spin}, Black!`)} 

if (spin %2===0){
  spin = "Red"
}
else{
  spin = "Black"
}

if (gamble === spin.toUpperCase()){
  console.log("Hurray!")
  wallet = (wallet+(bet*2))
  console.log(walletWeight())
}
else {
console.log("Damn You Lost!")
  wallet = (wallet-bet)
  console.log(walletWeight())
}
}

BlackOrRed()

函数BlackOrRed（）
{
钱包=500
函数walletWeight（）{
return`您的钱包中现在有$${wallet}。`}
var Red=[]
var Black=[]
对于（i=1；i