mongoose.connect(), first argument should be String, received undefined

Question

I am trying to set the test database for the testing purpose, but its not working.

I am trying to connect to mongodb using mongoose, but finding problem in connection er

Answer 1

i have encountered the same error, this thread didn't help... here's my solution it was simple! im using express, mongo, mongoose, and dotENV

file 1 === db.js

 import mongoose from 'mongoose';

const connectDB =  async ()=>{

    try{
        const conn = await mongoose.connect(process.env.MONGO_URI,{
            //must add in order to not get any error masseges:
            useUnifiedTopology:true,
            useNewUrlParser: true,
            useCreateIndex: true
        })
        console.log(`mongo database is connected!!! ${conn.connection.host} `)
    }catch(error){
        console.error(`Error: ${error} `)
        process.exit(1) //passing 1 - will exit the proccess with error
    }

}

export default connectDB

file 2= server.js

import express from 'express'
import dotenv from 'dotenv'
import connectDB from './config/db.js' // DB connection
import products from './data/products.js'

dotenv.config()
const PORT = process.env.PORT || 5000
const mode = process.env.NODE_ENV

const app = express()

connectDB() //this function connects us to the DB!!!
. . . more code…

> solution: the connectDB() expression must come after the dotenv.config() expression. and that's it ! :)