Model.remove not working

Backend Development
1

Tell us what’s happening:
Not quite sure what’s wrong with my code, but here’s the error it spits out.

POST
SyntaxError: Unexpected token o in JSON at position 1
at JSON.parse ()
at /home/runner/boilerplate-mongomongoose-1/server.js:346:29
at /home/runner/boilerplate-mongomongoose-1/node_modules/mongoose/lib/model.js:4999:18
at processTicksAndRejections (internal/process/task_queues.js:79:11)

Your code so far
https://boilerplate-mongomongoose-1.kyledute.repl.co/

Your browser information:

User Agent is: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/99.0.4844.82 Safari/537.36

Challenge: Delete Many Documents with model.remove()

Link to the challenge:

2

As I believe I mentioned before, this is what typically happens when you try to JSON parse something that is already an object. JSON.parse is expecting a string. If you pass something that is not a string, it will convert it to a string, presumably by using the built in toString method.

const myObj = { foo: 'bar' }

console.log(myObj)
// {foo: 'bar'}

console.log(myObj.toString())
// [object Object]

console.log(JSON.parse(myObj))
// throws error: Uncaught SyntaxError: Unexpected token o in JSON at position 1 at JSON.parse

What is happening? JSON.parse is getting that string. At position 0, it sees a “[”. No problem, JSON can be an array. It checks position 1, it is an “o”. That is impossible. There is no situation in JSON where that is a valid character in that position. The only things allowed there would be the start of a new array, the start of a new object, the start of a string (a double quote), the start of a number, the start of a boolean, or the start of null. And whitespace. Anything else is an invalid character. There are no variables in JSON so it can’t be that.

I can’t open up your repl right now for some reason. What I would recommend doing is going to the relevant JSON.parse and log out the data and type of that data on the line before. If it is not a JSON encoded string, then you should not be passing it to JSON.parse.

3

OK, found your repl at https://replit.com/@kyledute/boilerplate-mongomongoose-1.

So, you don’t have JSON.parse - so that must be happening somewhere else, perhaps internally in mongoose.

I don’t see anything wrong with your code. One thing I do notice is versions. In the beginning of this section you were told:

Add mongodb@~3.6.0 and mongoose@~5.4.0 to the project’s package.json

Now when I look in your package.json, I see:

        "mongodb": "^3.0.0",
        "mongoose": "^6.2.8"

Little things like that can make a big difference. Upgrading packages can break things - it should be done with caution.

4

Yup, changing the versions did the trick. You’re right, some of that got lost in the version control of trying to troubleshoot my previous issue. Thanks again Kevin!

1 Like
5

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