require('mongodb');
const bson = require('bson');

const mongoObjectId = new mongodb.ObjectId();

const bsonObjectId = new bson.ObjectId();

console.log(bson.EJSON.stringify(bsonObjectId)); // {"$oid":"5c092e78f381e590b57377c3"}
try {
    console.log(bson.EJSON.stringify(mongoObjectId));
} catch (e) {
    console.error(e) //Error: invalid ObjectId, ObjectId.id must be either a string or a Buffer, but is [{"type":"Buffer","data":[]}]
}