javascript - .map() 不是函数

Question

我正在尝试从费用数组中提取date、expenseInfo、category 和amount。但我得到 expenses.map() is not a function。

下面是代码。

我哪里错了？

let expenses = [{
    "user": {
      "id": "5bab847a5b0d2e2ce8b4cbe5",
      "name": "test_user",
      "email": "test@gmail.com",
      "username": "test"
    },
    "date": "07-Sep-2018",
    "expenseInfo": "Starbuck",
    "category": "Restaurants",
    "amount": 15
  },
  {
    "user": {
      "id": "5bab847a5b0d2e2ce8b4cbe5",
      "name": "test_user",
      "email": "test@gmail.com",
      "username": "test"
    },
    "date": "01-Aug-2018",
    "expenseInfo": "Shopping",
    "category": "Michael Kors bag",
    "amount": 90
  }
];

let expensesData = [];
let expenses1 = [];
expensesData.push(expenses);

expenses1 = expensesData.map((expense, index) => {
  `<tr>
          <td>${expense[index].date}</td>
          <td>${expense[index].expenseInfo}</td>
          <td>${expense[index].category}</td>
          <td>${expense[index].amount}</td>
           </tr>`
})

Answer 1

当您将费用压入费用数据时，您会在 第 0 个索引 处获得费用。您需要避免 push 或尝试下面的代码

let expenses = [{
        "user": {
          "id": "5bab847a5b0d2e2ce8b4cbe5",
          "name": "test_user",
          "email": "test@gmail.com",
          "username": "test"
        },
        "date": "07-Sep-2018",
        "expenseInfo": "Starbuck",
        "category": "Restaurants",
        "amount": 15
      },
      {
        "user": {
          "id": "5bab847a5b0d2e2ce8b4cbe5",
          "name": "test_user",
          "email": "test@gmail.com",
          "username": "test"
        },
        "date": "01-Aug-2018",
        "expenseInfo": "Shopping",
        "category": "Michael Kors bag",
        "amount": 90
      }
    ];

    let expensesData = [];
    let expenses1 = [];
    expensesData.push(expenses);

    expenses1 = expensesData[0].map((expense, index) => {
      `<tr>
              <td>${expense.date}</td>
              <td>${expense.expenseInfo}</td>
              <td>${expense.category}</td>
              <td>${expense.amount}</td>
               </tr>`
    })