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

If we don't want to define the path of the .env file like this,

require('dotenv').config({ path: 'ENV_FILENAME' });

we can place .env file in the same place as our main file, which was App.js in my case. So we could directly write

require('dotenv').config()

Answer 2

In the server directory,

1. npm install dotenv
   

2. In your server.js: If you use "type":"module" in your package.json file then,

   import dotenv from 'dotenv';
   import mongoose from 'mongoose'; 
   dotenv.config();
   

   or,

   const mongoose = require('mongoose')
   require('dotenv').config()
   

3. Add a .env file in the server directory,

   PORT=5000
   MONGO_URL= yourURL
   

4. In the server.js,

   const url = process.env.MONGO_URL
   mongoose.connect(url, { useNewUrlParser: true, useUnifiedTopology: true })
   .then(() => app.listen(PORT, () => console.log("Server up and running!")
   .catch((error) => console.log(error.message) 
   mongoose.set('useFindAndModify', false)
   

Answer 3

To read from .env file you have to install dotenv ( npm i dotenv / yarn add dotenv) and then just add this on top of your file.

const dotenv = require("dotenv");

dotenv.config();

Answer 4

I think you miss importing env file.

require('dotenv').config({ path: 'ENV_FILENAME' });

Answer 5

MongooseError: The uri parameter to openUri() must be a string, got "undefined". Make sure the first parameter to mongoose.connect() or mongoose.createConnection() is a string.

Answer 6

I had same error, for me it was because I was trying to use environment variables in globalSetup which had the file for initiating db connection.. mongoose.connect(global.__MONGO_URI__

Apparently, environment variables are not initialised yet in globalSetup so I had to move the code somewhere else, either to setupFilesAfterEnv or by using Async Test Environment