MongooseRor: el parámetro `Uri` a` OpenUri () `debe ser una cadena, se obtuvo" indefinido ". Asegúrese de que el primer parámetro para `Mongoose.connect ()` o `Mongoose.CreateConnection ()` es una cadena.

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

//If .env file is used in config folder, make sure the DB_STRING is associated with its
//value, which is the mongodb connection string from the cluster
//Next, install dotenv and require it in the app.js file:

require("dotenv").config({ path: "./config/.env" });
Depressed Dove