Node.js 无法在第一次连接时连接到服务器[localhost:27017]。[错误：在TCPConnectWrap.afterConnect[as oncomplete]处连接EconRefused---

我试图让mongo db存储数字1到9999，它将存储0到1，然后是0到2，以此类推

for(var i = 0; i <= 9999; ++i) {
    console.log(i);
    a += i + " ";
    add(a, i);
}

（变量i=0；i）的

{
const client=新的MongoClient（url）；
试一试{
等待client.connect（）；
const db=client.db（dbName）；
const addedItem=await db.collection（'nunb'）.insertOne（{num:item，LNUM:lastnum}）；
决议（增补条款[0]）；
client.close（）；
}捕获（错误）{
拒绝（错误）；
}
});
}
对于（var i=0；我请帮我解决这个问题…econnreference表示连接被主动拒绝，因为请求的端口上没有进程侦听。
var a = [];
const MongoClient = require('mongodb').MongoClient;
const url = "mongodb://localhost:27017/";
const dbName = 'numbzzz';

function add(item, lastnum) {
    return new Promise(async (resolve, reject) => {
        const client = new MongoClient(url);
        try {
            await client.connect();
            const db = client.db(dbName);
            const addedItem = await db.collection('nunb').insertOne({num: item, LNUM: lastnum});

            resolve(addedItem.ops[0]);
            client.close();
        } catch (error) {
            reject(error);
        }
    });
}

for(var i = 0; i <= 9999; ++i) {
    console.log(i);
    a += i + " ";
    add(a, i);
}

1
2
3
...
9999
(node:40664) [MONGODB DRIVER] Warning: Current Server Discovery and Monitoring engine is deprecated, and will be removed in a future version. To use the new Server Discover and Monitoring engine, pass option { useUnifiedTopology: true } to the MongoClient constructor.
(Use `node --trace-warnings ...` to show where the warning was created)
D:\codde\mongoDB test\node_modules\mongodb\lib\core\topologies\server.js:438
          new MongoNetworkError(
          ^

MongoNetworkError: failed to connect to server [localhost:27017] on first connect [Error: connect ECONNREFUSED 127.0.0.1:27017
    at TCPConnectWrap.afterConnect [as oncomplete] (node:net:1137:16) {
  name: 'MongoNetworkError'
}]
    at Pool.<anonymous> (D:\codde\mongoDB test\node_modules\mongodb\lib\core\topologies\server.js:438:11)
    at Pool.emit (node:events:378:20)
    at D:\codde\mongoDB test\node_modules\mongodb\lib\core\connection\pool.js:562:14
    at D:\codde\mongoDB test\node_modules\mongodb\lib\core\connection\pool.js:995:11
    at D:\codde\mongoDB test\node_modules\mongodb\lib\core\connection\connect.js:32:7
    at callback (D:\codde\mongoDB test\node_modules\mongodb\lib\core\connection\connect.js:280:5)
    at Socket.<anonymous> (D:\codde\mongoDB test\node_modules\mongodb\lib\core\connection\connect.js:310:7)
    at Object.onceWrapper (node:events:485:26)
    at Socket.emit (node:events:378:20)
    at emitErrorNT (node:internal/streams/destroy:188:8)

D:\codde\mongoDB test\node_modules\mongodb\lib\core\topologies\server.js:438
          new MongoNetworkError(
          ^

MongoNetworkError: failed to connect to server [localhost:27017] on first connect [Error: connect ECONNREFUSED 127.0.0.1:27017
    at TCPConnectWrap.afterConnect [as oncomplete] (node:net:1137:16) {
  name: 'MongoNetworkError'
}]
    at Pool.<anonymous> (D:\codde\mongoDB test\node_modules\mongodb\lib\core\topologies\server.js:438:11)
    at Pool.emit (node:events:378:20)
    at D:\codde\mongoDB test\node_modules\mongodb\lib\core\connection\pool.js:562:14
    at D:\codde\mongoDB test\node_modules\mongodb\lib\core\connection\pool.js:995:11
    at D:\codde\mongoDB test\node_modules\mongodb\lib\core\connection\connect.js:32:7
    at callback (D:\codde\mongoDB test\node_modules\mongodb\lib\core\connection\connect.js:280:5)
    at Socket.<anonymous> (D:\codde\mongoDB test\node_modules\mongodb\lib\core\connection\connect.js:310:7)
    at Object.onceWrapper (node:events:485:26)
    at Socket.emit (node:events:378:20)
    at emitErrorNT (node:internal/streams/destroy:188:8)