When I am using `req.body.post` in `Post.findById` it gives `undefined` but when I use direct `id` in `Post.findById` it workes fine.
`Console.log(req.body.post)` give correct id but using it in `Post.findById`
gives `undefined`
why `undefined` while console.log give correct id

```
const Post = require('../models/post');

module.exports.create = function(req,res){
    console.log(req.body.post);
    Post.findById(req.body.post,function(err,post){
        console.log(post);
        return res.redirect('/');
    })
}

```

```
Output
62175534d37c9ce165033cee 
undefined

```

when I use direct id which is `console.log` print then it works fine.

```
const Post = require('../models/post');

module.exports.create = function(req,res){
    console.log(req.body.post);
    Post.findById('62175534d37c9ce165033cee',function(err,post){
        console.log(post);
        return res.redirect('/');
    })
}

```

```
Output
{
  comment: [],
  _id: new ObjectId("62175534d37c9ce165033cee"),        
  content: 'sdf',
  user: new ObjectId("621749248e7de90faa6263d4"),       
  createdAt: 2022-02-24T09:51:48.621Z,
  updatedAt: 2022-02-24T09:51:48.621Z,
  __v: 0
}

```