Javascript 数组值未正确更新

我遇到了一个问题，我希望使用现有的数组，并使用for循环更新它的一个属性.我希望外部id和数组内的id匹配，例如:a&amp；a、b&amp；b、c&amp；c.然而，当我打印出最后一个数组时，所有内部id都设置为c.

我不明白为什么会发生这种事？

编辑:添加了预期yields

My Code个

  const accounts = [{ 
      "id": 1,
      "currency": "USD"
  }];

  const alphaId = ['a', 'b', 'c'];
  
  let finalArr = []; 

  for (index in alphaId) {
  
    let newAccount = {};
    newAccount.id = alphaId[index];
  
    newAccount.accounts = accounts;
    newAccount.accounts.forEach(acc => {
      acc.id = alphaId[index];
    });

    finalArr.push(newAccount);
  }

Print Out个

[
  {
    "id": "a",
    "accounts": [
      {
        "id": "c",
        "currency": "USD"
      }
    ]
  },
  {
    "id": "b",
    "accounts": [
      {
        "id": "c",
        "currency": "USD"
      }
    ]
  },
  {
    "id": "c",
    "accounts": [
      {
        "id": "c",
        "currency": "USD"
      }
    ]
  }
]

Expected Output个

[
  {
    "id": "a",
    "accounts": [
      {
        "id": "a",
        "currency": "USD"
      }
    ]
  },
  {
    "id": "b",
    "accounts": [
      {
        "id": "b",
        "currency": "USD"
      }
    ]
  },
  {
    "id": "c",
    "accounts": [
      {
        "id": "c",
        "currency": "USD"
      }
    ]
  }
]