I can use this code to get all the data from MongoDB.

import nextConnect from 'next-connect';
import middleware from '../database';

const handler = nextConnect();

handler.use(middleware);

handler.get(async (req, res) => {

    let doc = [];

    await req.db.collection("mountain").find().forEach(element => {
        doc.push(element);
    });
    console.log(doc);
    res.json(doc);
});

export default handler;

But I can't get the data with the condition.

import nextConnect from 'next-connect';
import middleware from '../database';

const handler = nextConnect();

handler.use(middleware);

handler.get(async (req, res) => {

    let doc = await req.db.collection("mountain").find({ name: "Lion Rock" })
    console.log(doc);
    res.json(doc);
});

export default handler;

The data in my MongoDB is like this:

Does anyone know where is the problem? Thank you!