在 Node.js 中连接到 mongoDB 时出错，“mongoose.connect() 的第一个参数是一个字符串。”

Question

I got error as below while running app.js

message: '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.',

name: 'MongooseError'

app.js file is as follow-

const express = require('express');
const path = require('path')
const dotenv = require('dotenv');
const  mongoose = require('mongoose');

const employeeRoutes = require('./routes/employee');
const app = express();

dotenv.config({path:'./config.env'});  //Setting configuration file

app.set('views',path.join(__dirname,'views')); //setting views folder
app.set('view engine','ejs');  //setting view engine as ejs
app.use(express.static('public')); //setting static folder

mongoose.connect(process.env.DATABSE_LOCAL.toString(),{      
useNewUrlParser : true,
useUnifiedTopology : true,
useCreateIndex : true 
});


const port = process.env.PORT;
app.listen(port,(port)=>{
 console.info("server started at 127.0.0.1:"+port);
});

this is my config.env

PORT = 3000
DATABASE_LOCAL = mongodb://localhost:27017/employees

Answer 1

I see what you are doing ; however you don't need to worry about using toString() method Simply leave it like this :

mongoose.connect(process.env.DATABASE_LOCAL)

The only reason it didn't work for you was because you had a small typo

mongoose.connect(process.env.DATABSE_LOCAL)