title: if (!db) throw new Error('missing db argument\nnew Grid(db, mongo)');^ Error: missing db argument new Grid(db, mongo)
body: <p>i want to connect to mongodb database using mongoose, the url is <code>http://localhost:27017/files</code> but i get the error which says </p>
  
  <pre><code>missing db argument
  new Grid(db, mongo)
  </code></pre>
  
  <p>what can be the problem given the code:</p>
  
  <pre><code>let express = require('express'); 
  let app = express(); 
  let bodyParser = require('body-parser');
  let mongoose = require('mongoose');
  mongoose.connect("http://localhost:27017/files",{useNewUrlParser:true});
  let conn=mongoose.connection;
  let multer=require('multer');
  let GridfsStorage=require("multer-gridfs-storage");
  let Grid=require("gridfs-stream");
  Grid.mongo=mongoose.mongo;
  let gfs=new Grid(conn.db);
  </code></pre>
  
  <p>the same question is already there in stackoverflow but the solution does not work for me and i have searched a lot on the internet but...<br>
  any help will be highly appreciated.</p>