Mongo DB.find returning empty array

Question

I have this line of code

    const comments = await db.Comment.find({post: req.params.post_id});
    return res.status(200).json({comments});

The request is being sent to the back-end successfully but the comments response is an empty array

/*
  res code: 200
*/

{
 comments: []
}

I checked other DB functions and they all work fine like adding a comment, editing it etc

my comment collection looks like this

{"_id":{"$oid":"605d1faeb202e4425c004be9"},"text":"Welcome to this comment","user":{"$oid":"5ff5d878dd830142686b7fd5"},"post":{"$oid":"6016f770ea76030d24688f89"},"createdAt":{"$date":{"$numberLong":"1616715694247"}},"updatedAt":{"$date":{"$numberLong":"1616715694247"}},"__v":{"$numberInt":"0"}}


--------------------------------------------------------
{"_id":{"$oid":"605d1fb8b202e4425c004bea"},"text":"Welcome to this comment2","user":{"$oid":"5ff5d878dd830142686b7fd5"},"post":{"$oid":"6016f770ea76030d24688f89"},"createdAt":{"$date":{"$numberLong":"1616715704381"}},"updatedAt":{"$date":{"$numberLong":"1616715704381"}},"__v":{"$numberInt":"0"}}

I am trying to search by post id which is saved as post in my comment Collection

`req.params.post_id` is a string, the `post` field is an ObjectId. See [Mongoose String to ObjectID](https://stackoverflow.com/questions/38446346/mongoose-string-to-objectid) — Joe, Mar 26 '21 at 00:27

fortunee · Accepted Answer · 2021-03-26T00:35:22.690

1

I think you need to wrap req.params.post_id in ObjectId.

Like this

const ObjectId = require('mongoose').Types.ObjectId;

const comments = await db.Comment.find({
   post: new ObjectId(req.params.post_id)
});

edited Mar 26 '21 at 00:35

answered Mar 26 '21 at 00:05

fortunee

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```Mongoose: comments.find({ 'post.$oid': '6059444e21d546156cfce227' }, { projection: {} })``` still doesn't work – Ahmed Gaafer Mar 26 '21 at 00:09
Did you get any errors? – fortunee Mar 26 '21 at 00:13
Or still an empty array? – fortunee Mar 26 '21 at 00:15
empty array was returned – Ahmed Gaafer Mar 26 '21 at 00:23
I think you need to wrap `req.params.post_id` in ObjectId. Try my updated answer – fortunee Mar 26 '21 at 00:35

Mongo DB.find returning empty array

1 Answers1