I am having a strange issue querying a Mongo DB collection. I am using findById() to get a single item that works sometimes and not others.

I have checked the id being passed to the server route and in all cases, they match perfectly with the targeted document in the collection.

Here is the basic code:

router.get("/:postId", async (req, res) => {
  console.log('id : ', req.params.postId)
  console.log('type: ', typeof(req.params.postId)) // id is a string
  try {
    const post = await Post.findById(req.params.postId).exec();
    console.log('post :', post) // sometimes null
    res.json(post);
  } catch (err) {
    res.json({ message: err });
  }
});

In the above route, only certain posts will be found while others come back null. This happens regardless of whether the id passed is correct and the document exists with the exact id.

If anyone has any ideas about what could be going wrong here I'd much appreciate the help!

EDIT

I have done some more debugging and think it is something to do with the Schema for the Post model.

For example, this object will be found:

{
"tags": ["foo"],
"_id": "8394839483fhg020834903",
"title": "bar",
"content": "baz",
"isPrivate": true,
}

But this one will not because of the missing isPrivate property.

{
"tags": [],
"_id": "5e0fdc631ef5c46b285a4734",
"title": "New post",
"content": "Some content here",
}

I have tested this across multiple queries and it appears to the root of the problem.

I have tried adding

isPrivate: {
    required: false
  }

To the Schema but it doesn't seem to solve the issue.

Here is the full Schema

const postSchema = mongoose.Schema({
  title: {
    type: String,
    required: true
  },
  content: {
    type: String,
    required: true
  },
  tags: [{ type: String }],
  date: {
    type: Date,
    default: Date.now
  },
  isPrivate: {
    type: Boolean
    required: false
  }
});

I'm not a Mongo/Mongoose expert, so any guidance would be much appreciated.