node.js - 如何在 mongodb 驱动程序中切换数据库？

const MongoClient = require('mongodb').MongoClient;
const uri = "mongodb+srv://<username>:<password>@<cluster>.mongodb.net/<dbname>?retryWrites=true&w=majority";

MongoClient.connect(uri, { useNewUrlParser: true, useUnifiedTopology: true }, function(err, client) {
  if (err) throw err;
  const db = client.db("new_database_name");
  console.log("Database changed to new_database_name");
  client.close();
});

const MongoClient = require('mongodb').MongoClient;
const uri = "mongodb+srv://<username>:<password>@<cluster>.mongodb.net/<dbname>?retryWrites=true&w=majority";

MongoClient.connect(uri, { useNewUrlParser: true, useUnifiedTopology: true }, function(err, client) {
  if (err) throw err;
  const db = client.db("new_database_name");
  console.log("Database changed to new_database_name");
  client.close();
});