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

const db = process.env.MONGO || 'test'    
    
mongoose.connect(db, {
      useNewUrlParser: true,
      useUnifiedTopology:true,
      useCreateIndex: true
    }).then(()=>{
      console.log("conected to mongodb");
    }).catch(error => {
      console.log("mongo error",error);
    })