I got an error when I run the code.Is there any errors in my code? This is the code that I enterd.

 const express = require("express");
const mongoose= require("mongoose");
const bodyParser = require("body-parser");
const cors = require("cors");
const dotenv=require("dotenv");
const app = express();
require("dotenv").config();

const PORT =process.env.PORT || 8070;

app.use(cors());
app.use(bodyParser.json());

const URL = process.env.MONGODB_URL;

mongoose.connect(URL, {
    useCreateIndex: true,
    useNewUrlParser:true,
    useUnifieldTopologyL:true,
    useFindAndModify:false,
});

const connection = mongoose.connection;
connection.once("open", () => {
    console.log("Mongodb Connection success!");
})

app.listen(PORT, () => {
    console.log('Server is up and running on port number: ${PORT}')
})

i got this error when I give npm start command

backend@1.0.0 start C:\Users\Admin\Desktop\cosmetic\backend node server.js

Server is up and running on port number: ${PORT} (node:4808) UnhandledPromiseRejectionWarning: MongoParseError: options usecreateindex, useunifieldtopologyl, usefindandmodify are not supported at Object.parseOptions (C:\Users\Admin\Desktop\cosmetic\backend\node_modules\mongodb\lib\connection_string.js:281:15) at new MongoClient (C:\Users\Admin\Desktop\cosmetic\backend\node_modules\mongodb\lib\mongo_client.js:62:46) at C:\Users\Admin\Desktop\cosmetic\backend\node_modules\mongoose\lib\connection.js:781:16 at new Promise () at NativeConnection.Connection.openUri (C:\Users\Admin\Desktop\cosmetic\backend\node_modules\mongoose\lib\connection.js:778:19) at C:\Users\Admin\Desktop\cosmetic\backend\node_modules\mongoose\lib\index.js:330:10 at C:\Users\Admin\Desktop\cosmetic\backend\node_modules\mongoose\lib\helpers\promiseOrCallback.js:32:5 at new Promise () at promiseOrCallback (C:\Users\Admin\Desktop\cosmetic\backend\node_modules\mongoose\lib\helpers\promiseOrCallback.js:31:10) at Mongoose._promiseOrCallback (C:\Users\Admin\Desktop\cosmetic\backend\node_modules\mongoose\lib\index.js:1151:10) (Use node --trace-warnings ... to show where the warning was created) (node:4808) 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:4808) [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.