node.js - 在 res.send 期间更改了 JS 对象

Question

我在使用 Express 以 RESTful API 发送对象时遇到了一些麻烦。这应该很简单，但我有一个奇怪的错误。
这是我的代码:

result = result.map(function (elem) {
  elem.progress = elem.progress.map(prog => prog.progress).reduce((x, y)  => x + y, 0);
  return ({'user': elem});
});
result.forEach((elem) => console.log('#', elem.user.progress));
console.log('result:', result);
res.send(result);

这是我用来测试它的数据:

[
  {
    "user": {
      "user_id": 1,
      "id": 354,
      "already_connected": 1,
      "progress": [
        {
          "id": 520,
          "teams_user_id": 354,
          "a_category_id": 1,
          "progress": 100,
          "created": "2016-11-10T13:44:30.000Z",
          "modified": "2016-11-10T13:44:33.000Z"
        },
        {
          "id": 521,
          "teams_user_id": 354,
          "a_category_id": 2,
          "progress": 100,
          "created": "2016-11-10T13:44:33.000Z",
          "modified": "2016-11-10T13:44:35.000Z"
        },
      ],
      "user": {
        "name": "Foo bar",
        "avatar_id": 6673,
        "default_avatar_int": 1
      }
    }
  }
]

我期望progress等于200，这是我在res.send之前做console.log的情况，但是当我在Postman中接收数据时，progress仍然等于一个数组。我究竟做错了什么 ？

Answer 1

如果这是您最初使用的数据，那么您可能忘记导航到 .user 属性。检查这个:

var result = [
  {
    "user": {
      "user_id": 1,
      "id": 354,
      "already_connected": 1,
      "progress": [
        {
          "id": 520,
          "teams_user_id": 354,
          "a_category_id": 1,
          "progress": 100,
          "created": "2016-11-10T13:44:30.000Z",
          "modified": "2016-11-10T13:44:33.000Z"
        },
        {
          "id": 521,
          "teams_user_id": 354,
          "a_category_id": 2,
          "progress": 100,
          "created": "2016-11-10T13:44:33.000Z",
          "modified": "2016-11-10T13:44:35.000Z"
        },
      ],
      "user": {
        "name": "Foo bar",
        "avatar_id": 6673,
        "default_avatar_int": 1
      }
    }
  }
]

result = result.map(function (elem) {
  // you forgot to navigate to `.user` property
  elem.progress = elem.user.progress.map(prog => prog.progress).reduce((x, y)  => x + y, 0);
  return ({'user': elem});
});
result.forEach((elem) => console.log('#', elem.user.progress));
console.log('result:', result);