Type Error when using ObjectId class in MongoDB Node JS Rest API-CodePudding

I am creating the rest APIs using Next Js and MongoDB, with Type Script checking. When creating one of the routes to fetch the post by Id, I get the following error:

(property) NextApiRequest.query: Partial<{
    [key: string]: string | string[];
}>
Object of query values from url

Argument of type 'string | string[] | undefined' is not assignable to parameter of type 'string | number | ObjectId | ObjectIdLike | Buffer | Uint8Array | undefined'.
  Type 'string[]' is not assignable to type 'string | number | ObjectId | ObjectIdLike | Buffer | Uint8Array | undefined'.
    Type 'string[]' is missing the following properties from type 'Uint8Array': BYTES_PER_ELEMENT, buffer, byteLength, byteOffset, and 3 more.ts(2345)

This is my API Code:

import nc from "next-connect";
import { ObjectId } from "mongodb";

import clientPromise from "../../../../../lib/mongodb";

import type { NextApiRequest, NextApiResponse } from "next";

const one rror = (
  err: any,
  _req: NextApiRequest,
  res: NextApiResponse,
  next: any
) => {
  console.error(err);

  res.status(500).end(err.toString());
  // OR: you may want to continue
  next();
};

const handler = nc({
  one rror,
})
  .get(async (_req: NextApiRequest, res: NextApiResponse) => {
    
    const client = await clientPromise;
    const db = client.db(process.env.MONGO_DB);

    try {
      const _id = new ObjectId(_req.query.postId); // gets the type error here

      const result = await db.collection("posts").findOne({ _id });

      res.json(result);
    } catch (error) {
      console.log("show error", error);
      res.send({
        status: 400,
        message: "Internal Server Error" || error,
      });
    }
  })

I also tried passing default values while destructuring the postId from the _req.query, something like this:

const { postId = '' } = _req.query || { };
const result = await db.collection("posts").findOne({ _id: new ObjectId(postId) }); // gets the type error here as well

But still, the error persists.

The only way the error goes away is if I don't wrap the ID with the new ObjectId class, but then that does not fetch any result from the database. Which is valid in itself. The document id is a type of object id, hence needs to be added.

I am pretty new to the Next Js and API creation using the same framework. Any help to resolve and understand this issue will be appreciated.

CodePudding user response：

ObjectId accepts this type

'string | number | ObjectId | ObjectIdLike | Buffer | Uint8Array | undefined'

however type of query value is : string | string[] | undefined

string[] is not common. try this

const _id = new ObjectId(_req.query.postId as unknown as string);

if you dont want type casting, you could use

let _id;
if (ObjectId.isValid(_req.query.postId)){
     _id = new ObjectId(_req.query.postId);
}
// then if _id exists run the query

if(_id){
    const result = await db.collection("posts").findOne({ _id });
    res.json(result)
}