当我尝试连接到 mongodb 时出现此错误

Question

Here is my NodeJS code

const express = require('express'); 
const cors = require('cors'); 
const mongoose = require('mongoose'); 
require('dotenv').config(); 
const app = express(); 
const port = process.env.PORT || 6000; 
app.use(cors()); 
app.use(express.json()); 

const uri = process.env.ATLAS_URI; 
mongoose.connect(uri, { useNewUrlParser: true, useCreateIndex: true } ); 

const connection = mongoose.connection; 
connection.once('open', () => { 
    console.log("MongoDB database connection established successfully"); 
}) 

app.listen(port, () => { console.log(`Server is running on port: ${port}`); });

This is the .env file:

ATLAS_URI = mongodb+srv://xxxxxx:xxxxxx@cluster0.jnk3w.mongodb.net/xxxxxx?retryWrites=true&w=majority

This is the error log

(node:3812) UnhandledPromiseRejectionWarning: MongoParseError: option usecreateindex is not supported at Object.parseOptions (D:\\Front_end\\MERN_STACK\\Trackerapp\\tracker\\backend\\node_modules\\mongodb\\lib\\connection_string.js:281:15)

 at new MongoClient (D:\\Front_end\\MERN_STACK\\Trackerapp\\tracker\\backend\\node_modules\\mongodb\\lib\\mongo_client.js:62:46) at D:\\Front_end\\MERN_STACK\\Trackerapp\\tracker\\backend\\node_modules\\mongoose\\lib\\connection.js:785:16 at new Promise (<anonymous>) at NativeConnection.Connection.openUri (D:\\Front_end\\MERN_STACK\\Trackerapp\\tracker\\backend\\node_modules\\mongoose\\lib\\connection.js:782:19) at D:\\Front_end\\MERN_STACK\\Trackerapp\\tracker\\backend\\node_modules\\mongoose\\lib\\index.js:330:10 at D:\\Front_end\\MERN_STACK\\Trackerapp\\tracker\\backend\\node_modules\\mongoose\\lib\\helpers\\promiseOrCallback.js:32:5 at new Promise (<anonymous>) at promiseOrCallback (D:\\Front_end\\MERN_STACK\\Trackerapp\\tracker\\backend\\node_modules\\mongoose\\lib\\helpers\\promiseOrCallback.js:31:10) at Mongoose._promiseOrCallback (D:\\Front_end\\MERN_STACK\\Trackerapp\\tracker\\backend\\node_modules\\mongoose\\lib\\index.js:1151:10)

(Use node --trace-warnings ... to show where the warning was created) (node:3812) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). To terminate the node process on unhandled promise rejection, use the CLI flag --unhandled-rejections=strict (see https://nodejs.org/api/cli.html#cli_unhandled_rejections_mode ). (rejection id: 2) (node:3812) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.

Answer 1

现在在版本> 6 的猫鼬你不要添加useCreateIndex: true, useNewUrlParser: true, useUnifiedTopology: true,你可以简单地写{mongoose.connect(uri, {});} useCreateIndex: true, useNewUrlParser: true, useUnifiedTopology: true, {mongoose.connect(uri, {});}

Answer 2

As of version 6.x of mongoose, it is no longer necessary to specify useNewUrlParser: true and useCreateIndex: true . You can simply leave those options out, your code should work then.

You can read more about it in the mongoose v6.x migration guide .