Question

我正在尝试fetch共同的朋友，并将他们置于共同朋友的财产中。但是，在res.send()函数的users对象中，它不包含共同的朋友属性

   router.get('/friends', auth, async (req, res) => {
   try {
      let users = await User.find({
         friends: req.user._id
      })
      users.map((user) => {
         let userAltered = {
            ...user.toObject()
         }
         userAltered.userImage = userAltered.userImageThumbnail;
         delete userAltered.userImageThumbnail;
         userAltered.mutualFriends = [];
         userAltered.friends.forEach((friend) => {
            if (req.user.friends.findIndex((myFriend) => {
                  return friend.toString() == myFriend.toString()
               }) > 0) {
               userAltered.mutualFriends.push(friend);
            }
         })
         return userAltered;
      })
      res.send({
         users,
         loggedInUserId: req.user.id
      });
   } catch (e) {
      res.status(500).send(e);
   }
})

Answer 1

查询返回的users对象将处于不可变状态。您需要先将其转换为javascript对象。当前，只有users内的对象被转换为对象，由于users列表本身是不可变的，因此更改将不会应用于它。

对于您而言，您需要先执行此操作

const result = users.map(u => u.toObject());

router.get("/friends", auth, async (req, res) => {
  try {
    let users = await User.find({
      friends: req.user._id,
    });
    const result = users.map((u) => u.toObject());
    result.map((user) => {
      user.userImage = user.userImageThumbnail;
      delete user.userImageThumbnail;
      user.mutualFriends = [];
      user.friends.forEach((friend) => {
        if (
          req.user.friends.findIndex((myFriend) => {
            return friend.toString() == myFriend.toString();
          }) > 0
        ) {
            user.mutualFriends.push(friend);
        }
      });
      return user;
    });
    res.send({
      result, // returning result object
      loggedInUserId: req.user.id,
    });
  } catch (e) {
    res.status(500).send(e);
  }
});

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