I have an error about mongoose Error: Arguments must be aggregate pipeline operators-CodePudding

Hi I'm new to the mongoose I got an error that Error: Arguments must be aggregate pipeline operators this

I just try to get posts from users who I'm following

I have no idea to solve this problem. It's my first time using aggregate function

here's my code

export const getPosts = async (req, res) => {
  const user = req.user;
  console.log(user);
  try {
    if (user.following.length === 0) return res.json("No following users");
    //user.following = string[]
    const followingPosts = await Post.aggregate([
      {
        $match: {
          userId: { $in: user.following },
        },
        $sort: {
          createdAt: 1,
        },
        $limit: 10,
      },
    ]);

    res.status(200).json(followingPosts);
  } catch (error) {
    console.log(error);
    res.status(404).json({ message: error.message });
  }
};

is there a good way to solve this problem let me know I'd really appreciate it. thanks for reading my qeustion

CodePudding user response：

Your query is syntactically wrong, you are creating one single object for different stages, and mongo expects each stage to be a separate object.

const followingPosts = await Post.aggregate([
  {
    $match: {
      userId: { $in: user.following },
    },
    $sort: {
      createdAt: 1,
    },
    $limit: 10,
  },
]);

The above syntax is wrong. Try this:

const followingPosts = await Post.aggregate([
  {
    $match: {
      userId: { $in: user.following },
    }
  },
  {  
    $sort: {
      createdAt: 1,
    },
  },
  {
    $limit: 10,
  },
]);